Two novel patterns of droplets, namely, hybrid asymmetric splitting mode and sorting patterns, have been observed by imposing an electric field in one branch of the microchannel. It is also concluded that using an electric field is a promising strategy to reach droplets with arbitrary sizes and control over the splitting ratio of daughter droplets precisely in a T- junction by adjusting the electric field strength. After a certain electric capillary number (* and Ca.In the current study, droplets dynamics under an asymmetric electric field in a T-junction are numerically studied using COMSOL Multi-physics software. The effect of different factors such as dimensionless length of mother droplet (L The ability to control the droplet size and sort them introduces many advantages such as cost reduction, higher efficiency, and improved safety in such systems. Aspects of droplet behavior such as coalescence4, trapping5, deformation6, fission8, formation18, and breakup31 were explored by researches in several geometries in a microfluidic network involving flow-focusing17, cross junction12, T-junction18, Co-flowing13, etc. The main approach to tune the size of droplets are T- and Y-junctions31.Nano and micro droplet formation has attracted attention in recent years due to its vast application in industries such as drug delivery28. Link et al.19 introduced two strategies to split up droplets asymmetrically. They used an isolated inside a straight channel. The primary disadvantage of this strategy is that a different process is needed to separate the generated small and large droplets after producing in which move together along the channel. Also, they proposed another available strategy for droplet breakup with different sizes by using a T-junction with different arms. Three different regimes were observed as a function of the droplet length and capillary number, including no breakup, breakup with tunnels, and breakup without tunnels obstruction22. It must be considered that both the pressure droplet and the manufacturing cost are increased in this system because the length of the arms must be increased. Ménétrier-Deremble and Tabeling20 experimentally investigated the asymmetric breakup of droplets in a λ-junction microchannel with arbitrary angles. They reported that the breakup volume ratio depends on the flow geometry only and is independent of the fluid characteristics and the flow conditions. The drawback of this method is that this method cannot produce the low volume ratio of droplets. Leshansky and Pismen23 presented a correlation for the critical droplet length (lCr) as a function of Ca number as 22. Similar to the correlation of Leshansky and Pismen23, Fu et al.24 proposed an improved power–law relationship as a and b are the fitting parameters which depend on the channel geometry and the viscosity ratio of the fluids. Bedram et al.26 numerically investigated the asymmetric breakup of droplets in T-junction microchannel with valve in one of the arms. They found out that smaller droplets in the arm with valve is generated by decreasing the capillary number. Moqadam et al.28 used a titled slat in the center of micro- and nano-scaled T-junctions to control the breakup ratio of droplets. They reported that their proposed system can generate droplets with small volume ratios, while the available methods are not able to achieve.The motion of the droplets can be modulated passively or actively. In passive microdevices, the droplet size significantly relies on the channel junctions and working fluids21, magnetic field27, micro-valves31, and electric field30. Besides the benefit of fast response time, another advantage of this method is that it is easy and reliable to precisely control the droplet's size and flexibility in changing the size. Ting et al.21 introduced a novel method for producing unequal-sized droplets by setting a heater at one of the branches of a T-junction microchannel. The disadvantage of this method is that the temperature does not reach values larger than 40˚C. Thus, its application is limited, especially for biological applications. Yoon et al.25 reported that mother droplet could be divided into daughter droplets in a wide range of the volume ratio by using two pneumatic valves located downstream of the bifurcating microchannel. This method has the main disadvantage as the structure of the valve affects the flow pressure and leads to difficulties in controlling the droplet breakup with a specified volume ratio. Ma et al.27 experimentally studied the breakup dynamics of ferrofluid droplets in T-junction microchannels induced by the magnetic field. They found that the magnetic force could affect the droplet breakup process and classified three different regimes: breakup without obstruction, breakup with part obstruction, and breakup with permanent obstruction. The main disadvantage of this mechanism is that generated droplets are equal, whereas, in some industries, like the pharmaceutical industry, droplets in various sizes are needed. Agnihotri et al.31 analyzed the capability for selective breakup at two locations using a T-junction and expansion channel by locally reducing the main channel width. They reported four different patterns: no droplet breakup in both junctions, droplet breakup in the first junction, droplet breakup in both junctions, and droplet breakup in the first junction onset of breakup in the second junction.Although this method can be fabricated easily, any change in size requires new geometry and configuration. This increases the cost and reduces the flexibility of the system. Also, sorting is an issue . There is a limit in the size ratio of the originated droplets to provide droplets with the desired size. Hence, the active technique is suggested to regulate droplets. This technique is achieved by applying an additional energy field involving temperature field.29 were one of the first groups to experimentally explain that applying an electric field is an effective strategy to manipulate and control the breakup, sorting, and coalescence in the microchannel. They applied an electric field parallel to the flow after the intersection of the symmetric T-junction microchannel. Jafari and Fallah30 numerically investigated the effects of electric field on droplet breakup in a symmetric T-junction microchannel. They showed that droplet splits faster in the presence of an electric field compared to the case without the electric field at the same condition. Yin et al.17 applied an AC electric field to adjust the droplet formation in the flow-focusing device. They found that the electrical frequency is directly correlated with the droplet formation regime's transition. Hatami et al.14 numerically modeled the droplet formation in the flow-focusing device under an electric field. Hatami et al.14 and Yin et al.17 do not work based on the breakup of droplets in which mother droplets split up two daughter droplets. Also, these methods generate droplets of one size, whereas they have the disadvantage of the method suggested by Ma et al.27.Several studies have shown that using an electric field as active control of droplets is more robust and faster than other active control methods. Link et ale), droplet length (L*), and Capillary number (Ca) in detail.This study proposes a new technique to use an electric field in a symmetric T-junction under the electric field in microchannels to regulate the size of the droplet and control the breakup speed, and sort the droplets simultaneously. Moreover, the effect of the electrical field on droplet breakup and the feasibility of applying an electrical field to control the size and breakup speed in droplet formation in microchannels is investigated numerically. The study is conducted by investigation of the important non-dimensional parameters involving electric Capillary number (Caw = 100 μm). The length of the main channel is 8w (L = 0.8 mm), and the horizontal ones are both 5w (z = 1.1 mm). As shown in Fig. L0, density ρd, viscosity μd, and relative permittivity of εd is moved by the continuous phase with density ρc, viscosity μc, and relative permittivity εc. The rear of droplet is placed L0/w = 0.3 from the inlet. A parabolic velocity profile is imposed on the inlet:u (m/s) and v (m/s) are the velocity components along the x and y directions, respectively, and y0 is the y-coordinate of the centerline of the vertical channel. Furthermore, a non-slip boundary condition is implemented for all the solid walls (u = v = 0). Also, a uniform relative pressure is set to a 0 Pa gauge pressure condition. A steady and uniform electric field (E) is generated along the y-direction as 0 and V0 are exerted to the lower wall and the upper wall of the left branch, respectively. Additionally, a zero-charge condition is applied for other boundaries.This study investigates the droplet deformation of a viscous fluid flowing in a symmetric T-junction microchannel Fig.  with nonThe physical properties of fluids are presented in Table ρ is density, μ viscosity, Uc is the inlet velocity of continuous phases, L0 is initial length of the droplet, relative permittivity is ε, E representing the uniform electric field strength, and interfacial tension between phases is shown by γ. The subscripts c and d represent continuous and dispersed phases, respectively. The density ratio (ρ*), viscosity ratio (μ*), and permittivity ratio (ε*) are kept constant for all the investigated cases. Electrical Capillary number (Cae) and permittivity ratio (ε*) are two factors used to represent the effect of the electric field on the process of droplet motion. The electrical Capillary number represents the ratio between the electric force and the interfacial tension force. Permittivity ratio describes the fluid response to the applied electric field. In this simulation, both phases are assumed incompressible and dielectric, and the permittivity of the continuous phase is assumed to be equal to the permittivity of the vacuum (ε0).The following non-dimensional numbers are introduced that describe the problem;p, ρ, u, Fe and Fγ represent the fluid pressure, the fluid density, the velocity vector, the electric force and the interfacial force of two immiscible fluids, respectively. Due to the small size of the microchannel and small density ratio, gravity is neglected.To investigate the dynamics of the droplet deformation, the Navier–Stokes equation should be solved numerically. We use the level-set method to capture the interface of the two immiscible phases. Besides, the interfacial force and the electrical force are added to the Navier–Stokes equation as source terms;, λ and By solving the transport equation of the Level-set asγ, κ and n denote the surface tension coefficient, the curvature of the interface, and the normal direction with respect to the droplet surface, respectively. δ is a Dirac Delta function.The level-set function (Φ) is defined as:32. The charge conservation can be written as:qv is the volume density of local free charges, σ represents the conductivity of the fluid. From Maxwell's equations, the electrical relaxation time of the droplet is given by εw = 80ε0, and σw = 5.0 × 10−4 S/m, yielding 33. Hence, the first term of Eq. (D = ε0εE) are also calculated accordingly. The divergence of the Maxwell stress tensor can determine the electric force asqv = 0) and incompressible fluid, Eq.  method has been implemented in industries to model real engineering problemsTo validate current results, two different cases are considered. First, the droplet motion in the microchannel is simulated to verify the flow field. Second, the deformation of a static droplet under the electric field is also examined to validate the application of the electric field.22 and the numerical results. They classified droplet motion processes in symmetric T-junctions microchannel into three different patterns as no breakup, breakup with tunnels, and break up with permanent obstruction patterns (without tunnels). The comparison reveals that the results have good agreement with experimental results in terms of the flow patterns.Figure 52 analytical relation. Assuming no contact between the wall and the disperse phase and small Reynolds number flow, Bretherton52 suggested an analytical correlation for the velocity of the disperse phase in a slender tube (U) with respect to the viscosity of continuous phase (μc), surface tension (γ), and the average velocity of the fluid flow . The second regime that we observe in the simulation result has a similar pattern to the SPO. However, by decreasing the size of the mother droplet and the electric force, the bulbs of the droplet on the junction cannot fill the whole channel, and therefore a tunnel will be created. These tunnels, which are shown in Fig. * = 10, lead to a lower pressure gradient in comparison to the SPO. But, this pressure is still enough for the droplet splitting, and we call this regime Splitting with Tunnel (SWT). Figure Figure * = 2.5 ε* = 36.4, Ca = 0.0134 and Cae = 0.0351, respectively. When the daughter droplet enters the left channel, the local electric potential and electric field change due to the change in the dielectric constant of the medium. Inside the droplet, however, these field lines are constantly distributed. Therefore, a non-uniform force field will be formed around the droplet. Since the electric field is stronger in a medium with higher permittivity, a stronger electric field is created inside the droplet leading to an electric gradient at the surface of the droplet. This leads to a force at the droplet surface pointing from the inside of the droplet to the outside  for Ca = 0.02684 and 0.04026. As can be seen, *. It is worth mentioning that this increment is more highlighted for ca = 0.02684. Achieved results indicates * is raised from L* = 3.0 to L* = 5.0 = 0.0268. However, raising Capillary number from Ca = 0.02684 to Ca = 0.04026 (about 50%) just increase * could be attained by the fitting numerical data as a, b, and c are reported in Table As mentioned in Fig. entclass1pt{minima*). It is defined as:* < 1 refers to the mother droplet breaks up asymmetrically. According to the previous studies, splitting of the mother droplet in the absence of an electric field crucially depends on dimensionless droplet length (L*) and capillary number (Ca). Another dimensionless that affects is the electric capillary number (Cae). Figure e on the splitting ratio at L*5.0 for Ca = 0.02684 and Ca = 0.04026, respectively. It is evident from this figure that the splitting ratio decreases with the increase of the Cae until a critical value. In fact, the electric force relative to the interfacial tension force enhances by the increment of Cae. Hence, more volume of mother droplet is drawn towards the left side of the channel in which mass center of mother droplet is pulled into the left branch, leads to more asymmetric splitting. Further increment of Cae beyond the critical value results in the whole mother droplet being shifted to the left branch causes to SR* = 0. Furthermore, the droplet with a higher amount of SR* is observed for Ca = 0.04026 compared with Ca = 0.02684 at a constant Cae. Also, a sudden level off up to 0 for SR* happens at lower Cae as the Ca decreases. It must be mentioned that similar trends are observed for other L*, but they are omitted for better view.A major benefit of using the electric field in the T-junctions is to break up precisely a mother droplet into arbitrary sizes. To exploit this benefit efficiently, it is essential to predict the splitting ratio of the droplets (SRmentclasspt{minima*), Capillary number (Ca), and electric Capillary number (Cae), are investigated and the following results are drawn:It is observed that the use of an asymmetric electric field directly affects the droplet splitting process and flow patterns in symmetric T-junctions microchannel and produces droplets with unequal size.Two novel patterns of droplets named Hybrid Asymmetric Splitting Mode (HASM) and sorting patterns may happen when the electric field imposes asymmetrically.*) and Capillary number resulting in the splitting ratio of the droplets (SR*) 0.There is a critical electric capillary number above (the sorting electric capillary number) that the non-splitting (NS) regime occurs for each dimensionless length of mother droplet (Le, the droplet with a higher amount of SR* is observed for Ca = 0.04026 compared with Ca = 0.02684. Also, a sudden level off up to 0 for SR* happens at lower Cae as the Ca decreases.At a constant CaThe current results indicate that the proposed novel method is a suitable approach to adjust actively the size of droplets.In the current study, the motion of droplet under an asymmetric electric field in the asymmetric T-junction microchannel is investigated numerically. To this approach, COMSOL Multi-physics software based on the Level Set method is adopted. The effects of various factors, namely the non-dimensional droplet length (L


Endovascular treatment (EVT) is considered a preferred procedure of superficial femoral artery (SFA) pseudoaneurysm in recent years. However, heterotopic ossification (HO) after SFA pseudoaneurysm is a rare occurrence, that may cause late stent–graft fracture.A 58-year-old male who underwent EVT for SFA pseudoaneurysm 8 years ago presented with a progressive mass at the right thigh and claudication. Computed tomography angiography (CTA) showed fracture and occlusion of stent–graft, which was compressed by the deep femoral artery (DFA) pseudoaneurysm and a bone-like body.According to the CTA images, the stent–graft was fractured and occluded, accompanied by DFA pseudoaneurysm.Debridement and arterial reconstruction were performed. Pathological analysis showed that the bone-like body was derived from HO. CTA at one-year follow-up showed that the prosthetic vessel was patent and previous hematoma disappeared.This report demonstrates that residual hematoma can induce HO, which may result in late stent fracture, and it should thus be removed timely. Patients with SFA pseudoaneurysm who have undergone EVT should be followed up regularly. Several works have reported acceptable long-term results, with 3-year patency rates ranging from 77.1% to 100%.,4 During EVT, the hematoma cannot be cleared away, and may be absorbed spontaneously in some cases.,6 However, the residual hematoma may lead to severe complications, such as infection and dysfunction of stent–graft. Here, we present a rare case of covered stent–graft fracture caused by heterotopic ossification (HO) of residual hematoma in a patient with SFA pseudoaneurysm treated by EVT 8 years ago.Development of pseudoaneurysm of lower limb arteries usually occurs due to trauma, infection, iatrogenic injury, or inflammatory process and can cause fatal or limb-threatening complications.2A 58-year-old man was stabbed by a sharp knife in his right thigh about 8 years ago, and he underwent debridement immediately after the stabbing in the local hospital. However, he presented with a pulsating mass soon after the debridement. He was then transferred to our hospital, and the angiogram demonstrated SFA pseudoaneurysm without defect of adjacent bone or other foreign bodies Fig. A. BecausRecently, this patient was readmitted to our institution with a complaint of a progressive mass in the right thigh and worsening symptoms of claudication. He denied drug abuse or other traumatic injuries. On physical examination, a huge tensive mass was found in the right thigh, and the skin temperature below the knee was lower than that at the contralateral limb. The pulses of ipsilateral popliteal and dorsal pedal arteries were not palpated. Computed tomography angiography (CTA) showed a 10 cm × 15 cm × 10 cm pseudoaneurysm, which was derived from a branch of deep femoral artery (DFA), and a foreign body of high density adjacent to the stent–graft. The stent–graft was fractured and occluded, and the femur was intact without any indications of fracture Fig. .The decision to perform OS was made considering the huge pseudoaneurysm, foreign body, and fractured stent–graft. During the operation, the hematoma was cleared away, and the bleeding branch of the deep femoral artery was ligated. Visual examination of the stent–graft showed a fracture, and its fabric was torn at the fractured part. The foreign body seemed like a piece of bone fragment Fig. A. The foCultures of the explanted stent–graft and hematoma showed no signs of infection. Pathological analysis of the foreign body revealed osseous tissues without lamellar structure, accompanied by proliferation of fibrous tissues and infiltration of inflammatory cells Fig. B. This r3 The traditional treatment for SFA pseudoaneurysm is surgical reconstruction, which is associated with severe complications, especially for patients with multiple comorbid conditions. EVT has been accepted as a minimally invasive procedure for SFA pseudoaneurysm. Authors had described a high long-term primary patency of EVT for SFA pseudoaneurysm, ranging from 77.1% to 100%.–4 Placement of a covered stent–graft has become common and is considered a treatment option for traumatic SFA pseudoaneurysm.,3,7 Our patient was found to have developed a traumatic pseudoaneurysm 8 years ago. He had already undergone debridement, and no foreign bodies were shown in his angiogram. Therefore, EVT was a reasonable treatment option for this condition at 8 years ago. However, complications related to this procedure and their clinical effects are particularly noteworthy.Pseudoaneurysm of SFA resulting from penetrating trauma is relatively uncommon and is associated with substantial morbidity and mortality.,9Stent fracture is a late complication that occurs rarely and may result in artery occlusion, rupture, or pseudoaneurysm formation. Given that SFA is a dynamic anatomical segment, rigid stents are prone to compression and fracture in this area. Self-expandable stent–grafts are recommended in SFA lesion because they are flexible and can resist external deformation. However, bare-metal self-expandable stent–grafts have also been described in cases of occlusive diseases related to SFA, with a reported fracture rate ranging from 3.6% to 37%.–3,5,7,10 The covered stent–graft, including Wallgraft and Hemobahn/Viabahn, is composed of a self-expandable stent covered with a thin layer of polycarbonate urethane membrane and exhibits better resistance to compression and torsion than a bare-metal stent graft. Tielliu et al reported that the Hemobahn/Viabahn stent–graft in the region of popliteal artery has a fracture rate of 16.7%, but no fracture of self-expandable covered stent has been reported in the SFA region. Therefore, fracture of covered stent–grafts in SFA is rare.We search literatures about EVT and SFA pseudoaneurysm since 1999 by using PubMed, and no fracture of self-expandable covered stent occurred. The hematoma of previous pseudoaneurysm is not cleared away during EVT, but may be absorbed spontaneously in most cases.,3,5,7 In the present case, the high-density foreign body was demonstrated to be heterotopic bone tissues by pathological analysis. These heterotopic bone tissues, which were derived from the residual hematoma, could be products of HO. The residual hematoma is usually accompanied by organization and proliferation, and HO may occur during this process. HO is a common complication after multiple forms of extensive trauma.,13 The branch of DFA was injured by this heterotopic bone, which caused the formation of a huge pseudoaneurysm. Furthermore, the heterotopic bone fragment was pushed close to the stent–graft by the progressive pseudoaneurysm. Eventually, the covered stent–graft was occluded and fractured because of persistent compression from this adjacent bone fragment and pseudoaneurysm. Similar cases have never been reported before, but our hypothesis was validated by imaging and pathological analysis.Compared with conventional surgical treatment, exclusion with a covered stent–graft is a minimally invasive procedure.,5 However, the residual hematoma can also cause late complications, such as infection, stent occlusion, or fracture. Therefore, residual hematoma needs timely removal when it persistently exists or complications occur. Moreover, this patient had no regular follow-up after EVT for SFA pseudoaneurysm, and he did not come to our hospital until the DFA pseudoaneurysm occurred and stent–graft was fractured. If he had undergone regular follow-up, the bone-like foreign body could have been discovered timely and removed before severe complications occurred. Patients with pseudoaneurysm after EVT need regular follow-up to prevent these severe complications.Considering that this late complication was caused by residual hematoma, OS may be a reasonable choice for this condition. Our patient had a good recovery and exhibited a long-term benefit after OS. Covered stenting has been well established for SFA pseudoaneurysm, and studies have revealed that hematoma after EVT may be absorbed spontaneously.The fracture and occlusion of self-expandable covered stent–graft is a rare complication after EVT. This case report demonstrates that the residual hematoma after EVT may induce HO, which can result in late stent fracture or other complications. Therefore, the residual hematoma needs timely removal when hematoma persistently exists or HO occurs. Our case also highlights the need for continuous follow-up of patients with SFA pseudoaneurysm who have undergone EVT.Conceptualization: Jinting Ge, Tiehao Wang, Jichun Zhao.Data curation: Jiarong Wang.Investigation: Jinting Ge, Jichun Zhao, Susu Lu.Supervision: Jichun Zhao, Ding Yuan.Visualization: Tiehao Wang, Susu Lu.Writing – original draft: Tiehao Wang.Writing – review & editing: Tiehao Wang, Jichun Zhao, Ding Yuan.


Few studies have investigated risk factors for dystocia in swine, although this birthing abnormality can compromise welfare of both sows and pigletsby increasing stillbirth rate and decreasing sow productivity. This study aimed to determine risk factors associated with dystocia at piglet levelin cloprostenol-induced farrowings. A dystocia event was recorded when a birth interval exceeded 45  Selection of large litter size in recent decadeshas resulted in increased farrowing duration , which compromises the welfare of both sows and piglets byincreasing dystocia rate  and stillbirth rate . In comparison to perinatalstillbirth, dystocia is an unattractive topic because it does not directly relate to the number of piglets born alive as does the stillbirth,resulting in underestimation of this farrowing abnormality.The incidence of dystocia is usually reported to be very low, that is, 0.25 %–3 % . However, recent studies defining dystocia as an birth interval of more than 30–60 Farrowing induction is used to increase farrowing supervision by forcing sows to farrow during working time . Prostaglandins and itsanalogues can be used for farrowing induction . Among them, cloprostenol is the most commonlyused drug, and when program starts at day 114 of gestation the stillbirth rate , farrowing duration , and birth interval  are usually foundunaltered.Several previous studies have assessed effects of various factors including litter size, gestation length, stillbirth, and birth weight on farrowingduration and birth interval . In a recent report,factors associated with dystocia in spontaneous farrowings were also documented . Nevertheless, studies on risk factors fordystocia, particularly in induced farrowings, are still inadequate. Therefore, this study aimed to investigate effects of various factors on dystociaat piglet level in cloprostenol-induced farrowings.22.1This study was waived from the animal care and use committee of Vietnam National University of Agriculture because it was conducted in a commercialpig farm outside the university where all procedures done on animals have been routinely practiced.2.2This observational study was conducted from September 2020 to January 2021 on a farm in Bac Ninh province in the north of Vietnam. Farrowing inductionwith a 3-week interval has been conducted routinely on this farm since 2017; therefore, sows enrolled in this study might have been induced in thisway before. During the study period, in each batch of farrowings about 70–80 Landrace 2.3Parity number was recorded from the sow card. Gestation length was derived from the information on date of insemination and date of farrowing. Litter sizewas the sum of the number of live-born, stillborn, and mummified piglets. Birth interval was the interval between the births of two successivepiglets. Birth order at which oxytocin  was used was recorded. There were no strict rules of oxytocin use, and itsuse was independent of birth interval. However, oxytocin was not injected before the birth of the fifth piglets. The use of manual extraction wasrestricted on this farm and was applied when there were signs of reproductive canal obstruction. Relative birth order (RBO) was calculated asfollowing: RBO This data set was initially used in another study investigating risk factors for intrapartum stillbirths . Allstillborn piglets therefore were necropsied for stillbirth classification. However, for the purpose of investigation of risk factors for dystocia,classification results were not presented in this study, and stillbirth as a whole was used as a risk factor for dystocia. A dystocia event wasrecorded when a birth interval exceeded 45 2.4Generalized linear mixed model (GLMM) was used to investigate the effect of different risk factors on dystocia at piglet level. In GLMMs sows nestedwithin farrowing batches were fitted as random factors to take into account potential difference in litters and in batches. Independent riskfactors were parity , gestation length . It seems that the incidence of dystocia in this animal had been underestimated since recent reports defining dystociabasing on birth interval have shown that this birthing abnormality is not uncommon. Oliveira et al. (2020) reported that about 11.0 %–16.8 %of cloprostenol-induced farrowings experienced at least one dystocia event. This incidence is several times higher in the study by Boonraungrodet al. (2018), where 33.8 %, 50.0 %, and 73.6 % of spontaneous, prostaglandin F2The effect of RBO on dystocia in cloprostenol-induced farrowings in the present study is similar to that in spontaneous farrowings in a previousreport  where incidence of dystocia decreased to RBO of 50 %–60 % and increased thereafter. Similarly, Kovarnaet al. (2020) found that birth interval was longest at birth order of 1–4, shortest at birth order of 9–12 and then increased. On the one hand, thequadratic effect of RBO on dystocia/birth interval may be the result of endocrinological change during parturition. Endogenous oxytocin concentrationin crated gilts was found to increase during the first hour of parturition and decrease thereafter . Increased oxytocinconcentration in the early stage of farrowing stimulates uterine contraction and fetal expulsion resulting in a decrease in dystocia rate in the firsthalf of the parturition. The lowest incidence of dystocia/birth interval reported at different birth order/RBO in different studies may be the resultof discrepancy in oxytocin release pattern of investigated sows which was reported by Oliviero et al. (2008). However, it is not known if the lowestdystocia rate/shortest birth interval coincides with highest blood concentration of oxytocin in the farrowing sows. Therefore, further studiesexploring the relationship between endogenous/exogenous oxytocin and dystocia are in need in order to establish effective strategies in using oxytocin (ifapplicable) aiming at reducing dystocia rate. On the other hand, the increased dystocia rate in the second half of parturition may partly be a resultof both decreased oxytocin release and uterine fatigue .Interestingly, the present study showed that birth weight was more significant than BMI and PI in explanation of dystocia in swine, although BMI and PIhave been reported to be more significant than birth weight and crown rump length concerning stillbirth . Positive effect of birth weight on dystocia in the present study agrees with the previously reported results . Also, other findings showed that bigger piglets had a higher risk of being hypoxic than smaller ones . Bigger piglets have thicker fetal membranes; therefore, it takes them longer to break theirmembrane before they can travel through the birth canal . Also, in comparison with smaller piglets, heavier pigletshave higher friction against reproductive tract. Furthermore, bigger piglets are longer, which also results in their slower movement during the fetalexpulsion process. The weight and length of the piglets, however, cannot fully explain their movement speed because the stillborn piglets in thisstudy was smaller . Therefore, larger litter size results in lower birth weight,which is the answer to the association between litter size and dystocia in the present study. It is difficult to fully understand the association ofparity and dystocia in the present study. Increased dystocia rate in the parity 1 sows can be the result of their narrower birth canals in comparisonwith sows in other parities and of their small litter size . Therefore, this stage is of most importance to be supervised. High-birth-weight piglets are more likely to be born with a dystociaevent. Moreover, moderate piglets had the lowest odds of dystocia. Therefore, it is suggested that selection for litters of high homogeneity andnutrition supplementation for increasing litter homogeneity may be approaches to reduce dystocia, which subsequently improves survivability of piglets and welfare of the sows.


Background: To compare the effects of empagliflozin and linagliptin use on kidney outcomes of type 2 diabetes mellitus (T2DM) patients in a real-world setting.Methods: The study involved a propensity score-matched cohort comprising new users of empagliflozin or linagliptin with T2DM between January 1, 2013 and December 31, 2018 from a large healthcare delivery system in Taiwan. Clinical outcomes assessed: acute kidney injury (AKI), post-AKI dialysis, and mortality. Cox proportional hazard model was used to estimate the relative risk of empagliflozin or linagliptin use; a linear mixed model was used to compare the average change in estimated glomerular filtration rate (eGFR) over time.Results: Of the 7,042 individuals, 67 of 3,521 (1.9%) in the empagliflozin group and 144 of 3,521 (4.1%) in the linagliptin group developed AKI during the 2 years follow-up. Patients in the empagliflozin group were at a 40% lower risk of developing AKI compared to those in the linagliptin group . Stratified analysis showed that empagliflozin users ≥65 years of age , or with a baseline eGFR <60 ml/min/1.73 m2 , or with a baseline glycohemoglobin ≦7%  experienced attenuated benefits with respect to AKI risk. A smaller decline in eGFR was observed in empagliflozin users compared to linagliptin users regardless of AKI occurrence .Conclusion: Empagliflozin users were at a lower risk of developing AKI and exhibited a smaller eGFR decline than linagliptin users. Thus, empagliflozin may be a safer alternative to linagliptin for T2DM patients. Type 2 diabetes mellitus (T2DM) is a globally recognized critical health issue that generates a heavy economic burden on public health systems . T2DM haSGLT2i inhibits sodium-glucose cotransporter 2 channels in the renal proximal tubules and enhances glucosuria , includiIn contrast, DPP4i is generally considered a safe GLA and causes a decrease in albuminuria, and thus it has neutral or even slightly beneficial effects on kidney . It is pThe one-on-one propensity score matched cohort of new users was sourced from the Chang Gung Research Database, a de-identified set of electronic health records from the network of Chang Gung Memorial Hospitals in Taiwan . The Cha2, kidney transplantation, dialysis, or glomerulonephritis. Further codes and operational definitions were detailed in The studied cohort consisted of patients with 1) two or more codes of International Classification of Diseases, Nineth and Tenth Revision, Clinical Modification  for T2DM with a minimum interval of 28 days from their last an outpatient setting or at least one inpatient claim, 2) at least one prescription of empagliflozin or linagliptin following the date of T2DM diagnosis between January 1, 2013, and December 31, 2018. The expense of GLAs use was covered by Taiwan National Health Insurance program only when patients fulfill the diagnostic criteria of American Diabetes Association guideline . The fir2]  changes from baseline were also compared between the two groups. The first episode of AKI was identified by an increase in serum creatinine (SCr) ≥0.3 mg/dl within 48 h, an increase in SCr to ≥1.5 times baseline within 7 days, or an increase in SCr to ≥4.0 mg/dl as defined by Kidney Disease: Improving Global Outcomes  2] . The meaBaseline variables, including patients’ demographic characteristics, laboratory data, comorbid conditions, and prior prescription use of drugs were identified . Baselinn (%) for categorical variables in the study cohort. The incidence rate of AKI  was assessed in the overall group and for both treatment groups. Kaplan-Meier analysis with log-rank test was employed to assess the cumulative incidence of AKI over the 2 years follow-up period in the matched cohort and stratified by the baseline eGFR categories (≥ and <60 ml/min/1.73 m2).Descriptive statistical analysis results of continuous variables were reported as mean and standard deviation or median and interquartile range, and data were summarized as To mimic a hypothetical random treatment allocation, individuals’ propensity scores for the initiation of empagliflozin or linagliptin treatment were first calculated based on the patient’s age, sex, baseline eGFR, Hemoglobin (Hb)A1C values, medication use, and comorbid conditions  using a The Cox proportional hazards regression model was used to estimate the adjusted hazard ratio (aHR) with 95% confidence interval (CI) for the effect of empagliflozin on the risk of AKI, after adjustments for age, sex, baseline laboratory results, comorbid conditions, and concomitant medication use was made . Changesn = 5,104) or linagliptin  during the study period  and a diabetes complication severity index score >0  were common among the patient cohort, as was hypertension  and hyperlipidemia . Around 26%  of the cohort had micro- or macro-proteinuria. New users of empagliflozin were younger and had higher mean eGFR at baseline compared with that of new users of linagliptin (p < 0.001 for both). Patient baseline characteristics before PSM are provided in The studied cohort comprised 11,830 T2DM patients who were prescribed empagliflozin  . The empThere were 211 episodes of AKI, 35 cases of dialysis after AKI, and 36 deaths during the 2 years follow-up period . The incp < 0.001) (2 subgroup (2 subgroup (p = 0.54). Empagliflozin was independently associated with a 40% lower risk of AKI compared with that seen among linagliptin users   . Similarsubgroup , but not= 0.001) .p = 0.0001); this was not seen among patients with HbA1C ≤7  (p = 0.002) and age <65 years old  compared to those of linagliptin users , empagliflozin users were found to be at a relatively lower risk of AKI compared to that of linagliptin users  . Empagliin users .2 per year) groups without adjusting for AKI incidence (p = 0.058)  after adjusting for age, sex, baseline HbA1C, and AKI event  . EmpagliKI event .2. Regardless of AKI development, a smaller decline in eGFR was noted in the empagliflozin group compared to that in the linagliptin group.The results of the 7,042 matched pairs of empagliflozin and linagliptin new user cohort study suggested that empagliflozin was associated with a lower risk of AKI during clinical management of T2DM. Compared with linagliptin, renoprotective effects of empagliflozin against AKI was greater in patients aged <65 years, with poor blood sugar control (HbA1C >7%), and baseline eGFR ≥60 ml/min/1.73 mAKI is recognized as a distinct risk factor for CKD progression and mortality. Timely identification of AKI development is a crucial strategy for CKD prevention in T2DM patients . To the 2 . Previous RCTs have shown no difference in the development of AKI with empagliflozin use compared to that of placebo use among T2DM patients with baseline eGFR between 45–60 ml/min/1.73 m3 . Recently Iskander et al. conducted a large retrospective cohort study and found that patients younger than 80 years who were new users of SGLT2i experienced lesser number of AKI events than those of DPP4i . In EMPA-REG OUTCOME trial, empagliflozin versus placebo showed no heterogeneity between male and female (p for interaction = 0.85) patients on the composite kidney outcome , empagliflozin is the preferred choice for treatment of T2DM with respect to the renoprotection.In conclusion, the use of empagliflozin versus linagliptin showed a reduced risk of AKI and slowed eGFR decline in a real-world T2DM population during a 24 months follow-up. In certain conditions, including a baseline eGFR of more than 60 ml/min/1.73 m


Despite 15–17 millions of annual births in China, there is a paucity of information on prevalence and outcome of preterm birth. We characterized the outcome of preterm births and hospitalized preterm infants by gestational age (GA) in Huai’an in 2015, an emerging prefectural region of China.Of 59,245 regional total births, clinical data on 2651 preterm births and 1941 hospitalized preterm neonates were extracted from Huai’an Women and Children’s Hospital (HWCH) and non-HWCH hospitals in 2018–2020. Preterm prevalence, morbidity and mortality rates were characterized and compared by hospital categories and GA spectra. Death risks of preterm births and hospitalized preterm infants in the whole region were analyzed with multivariable Poisson regression.< 7, and birth defects. For the hospitalized preterm infants, significantly in-hospital death risks were found in out-born of HWCH, GA < 32 weeks, birth weight <  1000 g, Apgar-5 min < 7, birth defects, respiratory distress syndrome, necrotizing enterocolitis and ventilation, whereas born in HWCH, antenatal glucocorticoids, cesarean delivery and surfactant use decreased the death risks.The prevalence of extreme, very, moderate, late and total preterm of the regional total births were 0.14, 0.53, 0.72, 3.08 and 4.47%, with GA-specific neonatal mortality rates being 44.4, 15.8, 3.7, 1.5 and 4.3%, respectively. There were 1025 (52.8% of whole region) preterm admissions in HWCH, with significantly lower in-hospital death rate of inborn  than out-born  infants. Compared to non-HWCH, three-fold more neonates in HWCH were under critical care with higher death rate, including most extremely preterm infants. Significantly all-death risks were found for the total preterm births in birth weight <  1000 g, GA < 32 weeks, amniotic fluid contamination, Apgar-5 min The integrated data revealed the prevalence, GA-specific morbidity and mortality rate of total preterm births and their hospitalization, demonstrating the efficiency of leading referral center and whole regional perinatal-neonatal network in China. The concept and protocol should be validated in further studies for prevention of preterm birth.The online version contains supplementary material available at 10.1186/s12884-021-03726-4. Perinatal and neonatal morbidity and mortality of preterm births represent the focus of quality improvement with perinatal healthcare strategies –5. DespiMany institute-based surveys and controlled studies may provide prevalence, morbidity and mortality as outcome of hospitalized preterm population or samples, however, reliable information in birth population-based outcome of hospitalized neonatal infants remains lacking from China. For prevention of preterm birth, perinatal and neonatal death, many efforts have been exerted in the past decade with the universal maternal-infant health insurance coverage as well as facility-based robust technologies, including antenatal care with fetal ultrasound monitoring, glucocorticosteroids, tocolysis, delivery resuscitation and neonatal intensive and critical care , 14–16. The national surveillance system reporting on perinatal information in China has limitations as it only retrieved data of preterm births ≥28 weeks of GA , 17–19. The current study aimed to delineate the prevalence, morbidity and mortality of whole regional preterm births and hospitalized infants stratified by GA, to investigate the role of Huai’an Women and Children’s Hospital (HWCH) as the main transferal center of whole region, and to verify the efficacy of perinatal interventions and the underlying neonatal morbidities of deaths. As birth population-based studies on perinatal and neonatal healthcare are still at preliminary stage in China , 12, 13,+ 0–36+ 6 weeks of GA, divided into extreme , very , moderate  and late  preterm groups . One-way analysis of variance or non-parametric Mann-Whitney test was used for comparison among groups. Categorical variables were presented as number and rate, using a two-tailed Pearson Chi-squared or Fisher’s exact test where appropriate. Of the 59,245 regional total births , 2651 (4.5%) were preterm in which 2527 women had fetal sonography early in pregnancy, with preterm perinatal and neonatal mortality rates being 8.4 and 4.3%, respectively  were born in HWCH, with significantly higher rates of major pregnancy complications and preterm birth (> three-fold) than those of non-HWCH hospitals  of death risks of the whole Huai’an region.


Studies assessing the association between short birth interval, a birth-to-birth interval of less than 33 months, and under-five undernutrition have produced inconclusive results. This study aimed to assess the relationship between short birth interval and outcomes of stunting, underweight, and wasting among children aged under-five in Ethiopia, and potential mediation of any associations by maternal anemia and baby birth size.Data from the 2016 Ethiopia Demographic and Health Survey (EDHS) was used. Stunting, wasting, and underweight among children aged under-five were outcome variables. Generalized Structural Equation Modeling (GSEM) was used to examine associations between short birth interval and outcomes, and to assess hypothesized mediation by maternal anemia and baby birth size.β = 0.337, p < 0.001 to β = 0.286, p < 0.001) and underweight . Maternal anemia and baby birth size mediated 4.2% and 4.6% of the total effect of short birth interval on stunting and underweight, respectively.Significant associations between short birth interval and stunting  and underweight  were found. There was no observed association between short birth interval and wasting . Maternal anemia and baby birth size had a significant partial mediation effect on the association between short birth interval and stunting (the coefficient reduced from Maternal anemia and baby birth size were identified as mediators of the association between short birth interval and under-five undernutrition status. Policies and programs targeting the reduction of under-five undernutrition should integrate strategies to reduce maternal anemia and small baby birth size in addition to short birth interval. According to the World Health Organization (WHO) recommendation, short birth interval is defined as a birth-to-birth interval of less than 33 months . Short bSome of the adverse child health outcomes associated with short birth intervals are preterm birth , 7 low bPrevious studies assessing associations between short birth interval and under-5 child undernutrition have been inconclusive. Undernutrition, in our study, refers to stunting (short-for-age), underweight (thin-for-age), and wasting (thin-for-height) . Some prOther limitation of previous work is the inclusion of maternal anemia , 19 and Seqota Declaration aiming to end malnutrition, particularly stunting, by 2030 [Africa and Asia bear the greatest share of all forms of malnutrition , 49. In  by 2030 , 52. It  by 2030 , 54. Nev by 2030 , requiri by 2030 –53.To the best of our knowledge, no previous study has investigated the mediation effect of maternal anemia and baby birth size in the association between short birth interval and under-five undernutrition . This study aimed to assess the mediation effect of maternal anemia and baby birth size in the association between short birth interval and under-five malnutrition; stunting, underweight, and wasting. The findings of this study will help policy makers and program planners consider the effect of short birth interval and potential mediators in combating undernutrition in Ethiopia.Data from the 2016 Ethiopia Demographic and Health Survey (EDHS) were used in this study. The EDHS is a nationally representative survey in Ethiopia and has been conducted every 5 years since 2000. The 2016 EDHS collected data on the nutritional status of children by measuring the weight and height of children under age 5 in all sampled households and comparing these to international standards . Weight Under-five undernutrition represented by stunting (a height-for-age Z-score below minus two standard deviations (-2 SD) from the median of the reference population), wasting (a weight-for-height Z-score below minus two standard deviations (-2 SD) from the median of the reference population), and underweight (a weight-for-age Z-score below minus two standard deviations (-2 SD) from the median of the reference population) were the outcome variables .Short birth interval, defined as a birth-to-birth interval of less than 33 months , was theMaternal anemia and birth size were the two sequential mediators considered in this analysis. Women’s blood samples were drawn from a drop of blood taken from a finger prick and collected in a microcuvette. Hemoglobin analysis was carried out on-site using a battery-operated portable HemoCue analyser , 57, 58.Maternal age, maternal education , maternal occupation , household wealth , place of residence , region , and total children ever born 1–2, 3–4, 5 +) were considered as potential covariates  mediated the observed relationships using mediation analysis. This is because, first, there has to be a significant association between the main exposure variable  and outcomes  to be mediated to further examine for the mediation effect of the potential mediators  [‘gsem’ command. First, the initial path models were fitted using exposure variable , potential mediators , and the outcomes . This was done to assess crude associations between the above-mentioned variables. Second, after controlling for potential confounders, the full mediation analysis models were fitted for each child undernutrition outcome separately. Each outcome variable was a binary variable analyzed assuming a Bernoulli response distribution and logit link function. Mediation can be either complete or partial [‘nlcom’ command was used to estimate the direct, indirect, total effects of short birth interval on child malnutrition. A p-value of < 0.05 was used to declare statistical significance. Statistical analysis was performed using Stata version 14 statistical software .Descriptive statistics (frequency with percent) were computed to describe the outcome  by the respondents’ characteristics. Pearson’s chi-squared tests were used to assess differences in stunting, wasting, and underweight frequencies by respondents’ characteristics. Sampling weight was considered to adjust for the non-proportional allocation of the sample to different regions, to their urban and rural areas, and the possible differences in response rates. Details about the weighting procedure can be found in the EDHS report . Multivais case) . Then, G partial , 62–64.  partial . A singl partial , 67. ForThe majority of stunting 78.1%), wasting (78.3%), and underweight (81.5%) were documented among children of women with no formal education. Similarly, 72.1% of stunting, 72.2% of wasting, and 73.9% of underweight were experienced by children of unemployed women. The prevalence of stunting, wasting, and underweight were higher (> 90.0% for each) among rural residents. About half of stunting, wasting, and underweight were among children born after a short birth interval  and underweight  were found. There was no significant association between short birth interval and wasting  . Significant associations were also found between short birth interval and maternal anemia , maternal anemia and baby birth size , and baby birth size and stunting . After conditioning on maternal anemia and baby birth size, the coefficient for short birth interval reduced in magnitude from path d, β = 0.337, p < 0.001 to path d’, β = 0.286, p < 0.001 . Significant associations were also found between short birth interval and maternal anemia , maternal anemia and baby birth size , and baby birth size and underweight . After conditioning on maternal anemia and baby birth size, the coefficient for short birth interval reduced in magnitude from path d, β = 0.449, p < 0.001 to path d’, β = 0.338, p < 0.001  should integrate strategies to reduce maternal anemia and small baby birth size in addition to the short birth interval. Health care providers should create awareness of the adverse effect of short birth interval on children's nutritional status. We also recommend women space births at least 33 months. Expanding postpartum contraception could help women prevent short birth interval. Longitudinal data is required to better estimate the causal effect of short birth interval and its associated mediators on child undernutrition.


To examine socioeconomic inequalities in birth outcomes among infants born between 2008 and 2018 and assessed trends in inequalities during that period in Colombia, a middle-income country with high levels of inequality emerging from a long internal armed conflict.Using birth certificate data in Colombia, we analysed the outcomes of low birth weight, an Apgar score <7 at 5 minutes after birth and the number of prenatal visits among full-term pregnancies. Maternal education and health insurance schemes were used as socioeconomic position (SEP) indicators. Inequalities were estimated using the prevalence/mean of the outcomes across categories of the SEP indicators and calculating the relative and slope indices of inequality .Among the 5,433,265 full-term singleton births analysed, there was a slight improvement in the outcomes analysed over the study period . We observed a general pattern of social gradients and significant relative (RII) and absolute (SII) inequalities for all outcomes across both SEP indicators. RII and SII estimates with their corresponding CIs revealed a general picture of no significant changes in inequalities over time, with some particular, time-dependent exceptions. When comparing the initial and final years of our study period, inequalities in low birth weight related to maternal education increased while those in Apgar score <7 decreased. Relative inequalities across health insurance schemes increased for the two birth outcomes but decreased for the number of prenatal visits.The lack of a consistent improvement in the magnitude of inequalities in birth outcomes over an 11-year period is a worrying issue because it could aggravate the cycle of inequality, given the influence of birth outcomes on health, social and economic outcomes throughout the life course. The findings of our analysis emphasize the importance of policies aimed at providing access to quality education and providing a health care system with universal coverage and high levels of integration. Maternal and birth outcomes such as birth weight and gestational age remain important public health indicators. These outcomes have been shown to influence health and wellbeing not only during childhood but also throughout the life course, having an impact on child development, cardiovascular diseases, all-cause mortality, and different social and economic outcomes in adulthood –5. BirthAdverse birth outcomes  disproportionately affect low- and middle-income countries , 9 and wAlthough largely preventable, adverse maternal and birth outcomes remain an important public health policy concern in many countries, including Colombia, where in recent years, reductions in perinatal and maternal deaths have stagnated , 18. AnaFew studies have examined inequalities in birth outcomes in middle-income countries and whether those inequalities have changed over time. Furthermore, to our knowledge, no previous study has quantified the magnitude of socioeconomic inequalities in birth outcomes in Colombia and described its changes over time. Using birth certificate data, our study examined socioeconomic inequalities in birth outcomes among infants born in Colombia between 2008 and 2018 and assessed trends in inequalities during that period. We used maternal education as an indicator of socioeconomic position (SEP), and given the special features of the Colombian health care system, inequalities by health insurance scheme were also examined.https://www.dane.gov.co). The birth certificate is completed in the health care facility where the birth occurred and is filled out by the health care professional (doctor or nurse) who delivered the infant. Community health workers and nursing assistants are also authorized to fill out the certificates, particularly in areas with health care provider shortages. According to the United Nations Demographic and Social Statistics and some studies carried out by independent organizations, the coverage and completeness of birth certificates in Colombia have greatly improved in the last years, going from 68% in 2000 to 97% in 2015 [Our study included all full-term live births (registered in birth certificate records) that occurred in Colombia between 2008 and 2018. Data were obtained from the Colombian National Department of Statistics (DANE), which collects and oversees birth certificate data. This open-access database is available through the DANE website , 5,859,208 full-term births were identified. The data were also limited to singleton births  and those with complete data on the study outcomes, SEP measures and covariates. All study variables had missing rates lower than 3.2%, and births excluded from the analysis due to missing data made up 6.5% of the initial number of full-term births identified. We preferred a full case analysis over a multiple imputation analysis because of the evidence suggesting a better performance of the former when the missingness is not as high as to jeopardize the validity of the study estimates and their precision . The finThis study was approved by the review board of the Faculty of Medicine from the Universidad Nacional de Colombia .We analysed socioeconomic inequalities in three primary outcomes: birth weight, Apgar score and number of prenatal visits. Due to concerns regarding potential identification of individuals, DANE only provides birth weight as a categorical measure in the publicly available birth certificate dataset. We examined binary indicators for low birth weight  and an Apgar score <7 at 5 minutes after birth . The numTwo measures of socioeconomic position were employed: maternal education and health insurance schemes. Maternal education was assessed as the highest education level achieved and categorized into primary school or less, secondary school, technical school, or university. Three categories of health insurance were used: contributory , subsidised, and uninsured. In Colombia, the provision of health care services is based on different health insurance schemes . Each faMaternal age, marital status, place of residence , region, child’s gender, the number of children the mother has had, and year of birth were used as control variables. In the analyses, these control variables were included in the regression models using the categories shown in First, we estimated the prevalence/mean of the outcomes by categories of the SEP indicators and assessed the significance of trends in these outcomes by using the chi square test for trend for the binary outcomes, and ANOVA for number of prenatal visits. Second, the relative index of inequality (RII) and slope index of inequality (SII) were derived to quantify inequalities in relative and absolute terms, respectively , 39. TheAmong the 5,433,265 full-term singleton births analysed for the whole study period, 2.4% were low birth weight, and 0.5% had an Apgar score <7 at five minutes after birth . The meaFor the period of interest, the prevalence/mean of the outcomes by education and health insurance scheme categories presented a general picture of social gradients in the expected direction, i.e., worse outcomes at successively lower SEP levels . Tests fRII and SII estimates showed significant relative and absolute inequalities across all years included in the analysis, all outcomes and all SEP indicators Figs  Tables. RII and SII estimates with their corresponding CIs revealed a general picture of no significant changes in inequalities over time, with some particular, time-dependent exceptions. For example, particularly high RII estimates were observed for Apgar score <7 by maternal education in 2014 and 2017, and by health insurance in the years 2011–2014 Figs  Tables. Regarding analysis by place of residence, there was not a clear and consistent pattern of inequalities across areas . Although inequalities in low birth weight were higher in urban areas for certain years, that was not consistent across the study period, the two SEP measures or nature of inequalities, i.e., absolute or relative .In this study, we examined socioeconomic inequalities in birth outcomes among infants born in Colombia between 2008 and 2018. Our results showed that among full-term singleton births, there was a slight improvement in the outcomes analysed i.e., lower low-birth-weight and Apgar<7 prevalence rates and higher number of prenatal visits. Interestingly, better birth outcomes and prenatal care estimates were observed in 2015, followed by higher prevalence rates for low birth weight and Apgar <7 and a lower number of prenatal visits in the last years of the time series. We found significant inequalities throughout the study period in all outcomes and across all SEP indicators, showing that the mother’s type of health insurance and education level are important drivers of inequalities in birth outcomes. Changes over time in the magnitude of those inequalities presented a mixed picture with differences according to the outcome, SEP indicator and whether inequalities were measured in relative or absolute terms. Overall, our analysis did not show consistent improvement, and in fact, some inequalities increased over the 11-year period studied.Although many different factors could contribute to an explanation of our finding of better outcomes in 2015 , we think that a potential explanation has to do with the dynamics of the internal armed conflict in Colombia. Specifically, the signing of the 2016 peace accord between the government and the FARC guerrillas was preceded by a definitive ceasefire in July 2015 that introduced differential changes in the levels of conflict violence across municipalities. This decrease in the intensity of conflict violence significantly improved pregnancy outcomes. The effects were larger for women living in municipalities where the intensity of FARC-related violence was historically greater .Our findings suggest that the mother’s health insurance scheme and education level are important determinants of birth outcomes in the Colombian context. The health insurance scheme does not seem to help address health inequalities, which has also been emphasized in other analyses with Colombian data , 44–46. The general picture of our findings showing no significant changes in the magnitude of inequalities over the study period, with just some exceptions, could be related to the fact that there have not been policy initiatives aimed to tackle key structural social determinants of maternal and child health in Colombia. Moreover, some significant higher relative inequalities observed for Apgar score<7 in certain years, e.g., 2014 could be a result of faster improvements in this outcome among the better educated mothers and those in the contributory or exceptional health insurance schemes.This is, to our knowledge, the first study to quantify the magnitude of inequalities in birth outcomes based on socioeconomic differences and to describe changes over time using birth certificate data covering virtually all births in Colombia. However, our findings should be interpreted with some caveats. First, births with incomplete data that were excluded from the analysis were more likely to be from rural areas, to have worse outcomes, and to be for mothers with lower educational levels or who are uninsured or in the subsidized scheme, than births included in the analysis . This maThe finding of consistently worse birth outcomes among more disadvantaged groups and the lack of a significant improvement in the magnitude of inequalities over an 11-year period is a particularly worrying issue because it could aggravate the cycle of inequality. This is, children born in socioeconomically disadvantaged circumstances are more likely to face difficulties during childhood, teenage years and even adulthood; given the influence of birth outcomes on health, social and economic outcomes throughout the life course. The findings in our analysis emphasize the importance of policies aimed at providing access to quality education and a health care system with universal coverage and high levels of integration. A real commitment to addressing health inequalities in Colombia means that policies and actions should not be focused only on the most disadvantaged but should aim at guaranteeing everyone opportunities and access to material and nonmaterial resources that are important for health . These aims should be part of a governmental and societal commitment to building a fairer society in the Colombian post-conflict era.S1 Fig(TIF)Click here for additional data file.S1 Table(DOCX)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.S3 Table(DOCX)Click here for additional data file.S4 Table(DOCX)Click here for additional data file.S5 Table(DOCX)Click here for additional data file.S6 Table(DOCX)Click here for additional data file.S7 Table(DOCX)Click here for additional data file.


What is the association of state-level criminalizing immigrant policies vs state-level inclusive immigrant policies with preterm births for immigrants and women of color in the US?In this cross-sectional study of 3 455 514 live births in 2018, criminalizing immigrant policies were associated with higher rates of preterm birth for Black women born outside the US, while inclusive immigrant policies were associated with lower preterm birth for all women born outside the US, particularly White women born outside the US.This cross-sectional study suggests that states that have enacted inclusive immigrant policies were associated with higher levels of preterm births among certain populations, even in the context of criminalizing policies. Criminalizing immigrant policies, a form of structural racism, are associated with preterm birth; however, to date, few population studies have examined this association by race and nativity status or examined the association of inclusive immigrant policies with preterm birth.To assess the extent to which variation in preterm birth by race/ethnicity and nativity status is associated with state-level criminalizing vs inclusive immigrant policies.This retrospective, cross-sectional study analyzed birth record data from all 50 states and the District of Columbia in 2018, as well as state-level indicators of inclusive and criminalizing immigrant policies. White, Black, Asian, and Latina women who had singleton births were included in the study. Statistical analysis was performed from June 1, 2020, to February 5, 2021. Two continuous variables were created to capture the number of criminalizing vs inclusive immigrant policies in effect as of 2017 in each state.The main outcome measure was preterm birth (<37 weeks’ gestation).Among the 3 455 514 live births that occurred in 2018, 10.0% were preterm, and 23.2% were to mothers born outside the US. Overall, for women born outside the US, each additional state-level inclusive policy was associated with a 2% decrease in preterm birth ; there were no significant associations between inclusive policies and preterm birth among women born in the US. In models examining the combined associations of criminalizing and inclusive immigrant policies with preterm birth, each additional criminalizing policy was associated with a 5% increase in preterm birth among Black women born outside the US . Each additional inclusive immigrant policy was associated with a lower likelihood of preterm birth for Asian women born in the US  and White women born outside the US . No significant associations were found among other groups.This study suggests that criminalizing immigrant policies are associated with an increase in preterm birth specifically for Black women born outside the US. Inclusive immigrant policies are associated with a decrease in preterm birth for immigrants overall, Asian women born in the US, and White women born outside the US. No associations were found between criminalizing or inclusive immigrant policies and preterm birth among Latina women. This cross-sectional study used US birth record data to assess the extent to which variation in preterm birth by race/ethnicity and nativity status is associated with state-level criminalizing or inclusive immigrant policies. High rates of preterm birth are a public health priority in the US, with rates for mothers born outside the US increasing steadily since 20145 while decreasing among mothers born in the US.6 Although the so-called healthy immigrant effect suggests that immigrants have better birth outcomes compared with women born in the US,7 there continues to be a debate about its applicability across immigrant groups, including the need to examine broader structural determinants and racial/ethnic heterogeneity within immigrant groups.9Exclusionary, criminalizing immigrant policies, a form of structural racism, are associated with increased adverse birth outcomes, including preterm birth.10 and remain embedded in societal norms.10 Policies criminalizing immigrants living in the US, as well as those promoting integration into social and economic institutions, have been enacted mostly at the state or county level during the last 20 years.11Structural racism refers to the historical and contemporary systems that produce and reproduce racial inequities through laws, policies, and practices that are implemented by different levels of government2 Data indicate an increase in preterm birth rates directly following the 2016 presidential election among immigrant and Latina women, suggesting that the acute stress of anti-immigrant rhetoric and changes in federal immigration policies immediately after the election resulted in an increase in preterm birth.13 Others have found a temporal trend between anti-immigrant rhetoric during pregnancy and subsequent inadequate prenatal care14 and low birth weight among Latina women born outside the US.2Although research is limited, there is growing evidence demonstrating that criminalizing immigrant policies are associated with adverse birth outcomes.13; there is a need to also examine the role of inclusive policies. Although immigrant policies may restrict or extend the rights of noncitizens,15 state-level inclusive policies expand immigrant rights and protections, such as access to children’s health insurance regardless of legal status or access to drivers’ licenses.16 These types of policies are important to examine because they serve as policy levers to reduce health inequities and may buffer the effects of a more exclusionary national climate and executive actions. In addition, most studies have focused on Latina women.18 Because of the unique histories and current practices of racialized exclusions across immigrant groups,19 it is critical to also examine the experiences of Black and Asian immigrant women. Finally, past studies have examined single policies2 or acute events.13 Because individuals experience the impact of an array of policies, the overall policy climate may be a critical marker of health because it captures the dynamics of both exclusion and inclusion. This overall policy climate may be particularly critical for maternal and child health development, for which the cumulative impact of exposures exceeds the impact of a singular policy.20There are several limitations in the current literature on immigrant policies and birth outcomes. Much of the literature on immigrant policy has focused on exclusionary, criminalizing policiesTo fill these gaps in the literature, we used national data on all US births in 2018 to examine the associations of criminalizing immigrant policies or inclusive immigrant policies with preterm birth. We also examined how these associations vary across nativity status for Black, Latina, Asian, and White women in the US. We hypothesized that states with higher criminalizing policies would be associated with higher levels of preterm birth, while higher inclusive policies would be associated with lower levels of preterm birth.STROBE) reporting guideline.This retrospective, cross-sectional study includes births from all 50 states and the District of Columbia in 2018. Birth record data were obtained from the National Center for Health Statistics. These data are deidentified and publicly available, and therefore the University of California, Los Angeles determined this study to be exempt from human participants review, and subsequently informed consent was not required. There were a total of 3 801 534 live births in the US in 2018. We excluded women with nonsingleton births, women who did not identify with one of our main race/ethnicity categories, and women who had missing covariates and outcome data  and from 0 to 14 for the inclusive immigrant policy variable (whereby an increasing score denoted a more inclusive immigrant policy context).Two continuous variables were created to capture the number of criminalizing and inclusive immigrant policies in effect as of December 31, 2017, in each state, referring to the preconception year prior to when women gave birth . The sel21; nativity (born outside the US vs born inside the US); age ; educational level ; smoked at any stage during pregnancy (yes or no); and insurance type . For the remainder of the article, non-Hispanic White women are referred to as “White,” non-Hispanic Black women are referred to as “Black,” and Hispanic women are referred to as “Latina.” State-level covariates include the percentage of each state’s residents born outside of the US in 2017,22 percentage living below the federal poverty level in 2017,23 and percentage of voters in the 2016 presidential election voting for the Republican presidential candidate.24Individual-level covariates were obtained from birth records and included self-reported maternal race/ethnicity , which was classified in accordance with the guidelines from the Office of Management and BudgetP < .05. All analyses were conducted using Stata, version 16 MP software (StataCorp LLC).25Statistical analysis was performed from June 1, 2020, to February 5, 2021. We calculated descriptive statistics across individual-level and state-level variables, including the percentage of preterm births across each variable. Mixed-effects multilevel logistic regression models were used to estimate the odds of preterm birth associated with a 1-unit increase in criminalizing and inclusive policies. An exploratory analysis of the policy indices included examining the distribution of preterm births by each policy level as well as plotting the estimated probabilities by preterm birth by increasing level of policy. Because there was a linear association between the policy indices and preterm birth, the policy indices were modeled as continuous variables  . We thenIn models examining the combined associations of criminalizing and inclusive policies with preterm birth, each additional state-level criminalizing policy was associated with a 5% increase in preterm birth among Black women born outside the US  . The assThis national study found that Black women born outside the US who lived in states with more criminalizing immigrant policies had higher odds of preterm birth. The study also found that, overall, immigrant women living in states with more inclusive policies were less likely to have preterm births, even in the context of criminalizing policies. However, there were significant racial/ethnic inequities in the protective associations of inclusive policies with preterm birth.26 disproportionately experience immigration enforcement. For example, despite being a population that is largely documented, Black immigrants with lawful permanent status are disproportionately deported based on criminal grounds.26 Thus, the presence of more criminalizing policies may increase fear and stress among Black women born outside the US who are concerned about the vulnerability of their legal status  and about the risk of entering the “prison-to-deportation pipeline” amid an already racist, punitive criminal justice system.27In particular, criminalizing policies were associated with a 5% higher odds of preterm birth for Black women born outside the US, even in the context of inclusive policies. This finding indicates that inclusive policies may not counter the negative association of criminalizing policies for Black women born outside the US. These findings may reflect a “double jeopardy” for Black women born outside the US who experience racial profiling and exclusion across both the criminal justice and immigration systems. This finding is consistent with other evidence that Black immigrants, despite being only 7% of the US population who were born outside the US,28 Most Black immigrants come from Caribbean or African countries where they are the racial majority,29 and thus they may be facing this racialization for the first time. Alternatively, these findings may reflect a “double invisibility” of Black immigrants, particularly in contexts with more criminalizing policies, whereby their minority racial/ethnic status and nativity status render their distinct needs unacknowledged and unaddressed in broader social and political institutions.28 The added psychological and economic distress may be associated with the short-term and long-term health of Black immigrant women before and during pregnancy.In addition, these findings suggest increased experiences of discrimination or “racialized othering” among Black immigrant women at the intersections of sex, race/ethnicity, and immigration status, which may be more common in states with criminalizing immigrant policies.10 including increasing maternal stress in utero.31 Although it remains unclear in what contexts and which particular subgroups of women are particularly susceptible to stress-induced physiological responses,32 a substantial body of literature points to the assocations between the important role of context, stress during pregnancy, and increased preterm birth risks.34 More proximal pathways linking policies to birth outcomes may include restricting access to health-promoting resources, such as prenatal care,35 public assistance, or follow-up visits,36 and impairing social capital and trust in public institutions.37Exclusionary state-level immigrant policies may operate through multiple complex pathways to produce inequities in birth outcomes,38 In the US, 16.7 million people nationwide live in a mixed-status family ,39 with 1.7 million undocumented Asian individuals living in the US.40 Moreover, knowing someone who has been deported, regardless of legal status, is associated with adverse health consequences.41 This study suggests that there may also be potential spillover effects of inclusive policies on Asian women. Further examination to unpack the heterogeneity of Asian people born in the US is warranted based on these findings.This study also found that inclusive policies were associated with a lower odds of preterm birth among immigrants overall, Asian women born in the US, and White women born outside the US. Asian women born in the US, but not Asian women born outside the US, were protected by inclusive policies. This outcome may be the result of “spillover effects,” or the impact of exclusionary policies and anti-immigrant rhetoric on the broader community regardless of their own legal status.42 with periodic anti-Muslim and anti-Chinese rhetoric, resulting in high levels of exposure to xenophobia and discrimination that may not vary significantly across states. It is possible, therefore, that the overarching national context surpasses state-level actions, resulting in less importance of state variation for Latinas. Moreover, other factors may be at play, including immigrant legal status and length of time in the US.In addition, this study found no significant associations for Latina women across nativity status. One hypothesis for this finding is that most of the anti-immigrant rhetoric has focused over time on Latinos,17 Such research is needed to inform and develop policy measures that are more reflective of immigrant women’s experiences of exclusion and inclusion across the life span. Finally, policy makers can address birth inequities through state-level and national-level policies that promote immigrant integration.This study has several research and public health implications. Given the increasing recognition of the critical role that structural racism plays in maternal health and birth outcomes, more research is needed to examine how criminalizing immigrant policies may harm the health of immigrants and how inclusive policies may buffer some of those harmful effects. Future research should examine how social policies are associated with immigrant reproductive health outcomes. Furthermore, there is a need to examine the association between immigrant policies and birth outcomes through an intersectional lens—one that recognizes the multiple social identities, processes, and statuses that may lead to experiences of exclusion.44This study has some limitations. First, we were unable to identify documentation status or time in the US from the National Center for Health Statistics data used. It is expected that those who are undocumented or lawful permanent residents (“green card” holders) and those who have lived in the US for longer periods would be the most impacted by both criminalizing and inclusive policies. However, past studies have reported mixed results when assessing birth outcomes across mothers’ documentation status.45 Another study found marked heterogeneity in birth outcomes comparing women born in the US with those born outside the US across numerous Asian subgroups.46 Moreover, in birth certificate data, “race” and “Hispanic ethnicity” are recorded as separate items; therefore, someone can identify as Hispanic ethnicity as well as White, Black, or other racial categories. However, evidence shows high validity between birth record data for race/ethnicity categories and self-reported identification.47Furthermore, this study did not include Pacific Islanders, nor did it assess heterogeneity across subgroups of Latina and non-Latina Black and Asian women. Previous studies have demonstrated that women born in sub-Saharan African countries have lower rates of preterm birth and small-for-gestational age offspring compared with Black women born in the Caribbean.Although this study accounted for a number of individual and state-level covariates, there may be unmeasured confounding and the possibility of findings being due to chance as a result of the large number of comparisons. This study also included cross-sectional data and is therefore unable to examine the causal effects of immigrant policies. Future studies examining dates of specific policy enactment could provide rigorous evidence on the association of immigrant policies with adverse birth outcomes.Despite these limitations, this study has several strengths. First, to our knowledge, there are few empirical studies that aim to quantify the association of structural racism with population health. These findings highlight the importance of interrogating inequities in birth outcomes through the lens of structural racism and how inclusive policies can counteract restrictive policies. Second, this study examines the overall policy context as opposed to a single policy. Third, this study uses national data to examine not only the experiences of Latina women but also other immigrant groups, including Black and Asian women.Criminalizing immigrant policies are associated with an increase in preterm birth specifically for Black women born outside the US. Inclusive immigrant policies are associated with a decrease in preterm birth for immigrants overall, with heterogeneity across race/ethnicity and nativity. Sociopolitical factors continue to be associated with racial/ethnic disparities in preterm birth for women born in the US or outside the US.


Preference for caesarean birth is associated with higher fear and lower self-efficacy for vaginal birth. Vicarious experience is a strong factor influencing self-efficacy in nulligravid women, and is increasingly accessible via digital and general media. This study assessed the effect of exposure to different birth stories on nulligravid women’s childbirth preferences and the factors mediating these effects.N = 426) were randomly allocated to one of four conditions exposing them to written birth stories. Stories varied by type of birth  and storyteller evaluation (positive/negative) in a 2 × 2 design. Childbirth preference, fear of labour and vaginal birth, and self-efficacy for vaginal birth were measured before and after exposure via a two-way between groups analysis of covariance. Hierarchical regression models were used to determine the mediating effects of change in childbirth fear and childbirth self-efficacy.Nulligravid women  = 44.78, p < 0.001). The effect of vaginal birth stories on preference was significantly mediated by fear of labour and vaginal birth and self-efficacy. Effects of exposure to caesarean birth stories were not explained by changes in fear or self-efficacy.Variations in type of birth and storyteller evaluation significantly influenced childbirth preferences (Childbirth preferences in nulligravid women can be significantly influenced by vicarious experiences. For stories about vaginal birth, the influence of birth stories on women’s fear and self-efficacy expectancy are partly responsible for this influence. The findings highlight the importance of monitoring bias in vicarious experiences, and may inform novel strategies to promote healthy childbirth.The online version contains supplementary material available at 10.1186/s12884-021-03944-w. Outcome expectancy did not, b =  − 0.17, 95 % CI, t(419) =  − 0.23, p = 0.820. As childbirth fear increased and childbirth self-efficacy expectancy decreased, preference towards caesarean birth increased. Childbirth fear was the stronger predictor of childbirth preference, and uniquely explained 2% of the variance in change in childbirth preference.Multiple regression indicated that birth story condition significantly predicted post-exposure measures for childbirth fear, Childbirth fear and self-efficacy expectancy varied significantly by experimental condition, and significantly predicted change in childbirth preference after controlling for the effect of experimental condition. Change in mediators between pre- and post-exposure to birth stories by condition are presented in Fig. Results for each step of the mediation analysis are presented in Table b =  − 7.73, 95 % CI, t(422) =  − 4.91, p < 0.001. Exposure to positive vaginal birth stories led to an increased preference towards vaginal birth while exposure to negative vaginal birth stories led to increased preference towards caesarean birth. When mediators were added to the model, experimental condition still significantly predicted childbirth preference, b =  − 5.21, 95 % CI, t(419) =  − 3.10, p = 0.002, however the relationship was weakened. The indirect effects of childbirth fear and self-efficacy expectancy were significant  =  − 2.93, p = 0.004 and childbirth self-efficacy expectancy, b =  − 0.28, 95 % CI, t(422) =  − 2.55, p = 0.011. After exposure to positive vaginal birth stories, outcome and self-efficacy expectancy increased, although the increase in outcome expectancy appeared to be small. Exposure to positive caesarean birth stories decreased childbirth outcome expectancy and resulted in a small increase in self-efficacy expectancy  significantly predicted childbirth fear Table . In posib =  − 7.20, 95 % CI, t(422) =  − 4.41, p < 0.001. When mediators were added to the model, the relationship between experimental condition and childbirth preference remained significant but weakened, b =  − 5.91, 95 % CI, t(419) =  − 3.59, p < 0.001. The indirect effects of childbirth fear and self-efficacy expectancy were significant  = 5.03, p < 0.001. When mediators were added, experimental condition still significantly predicted childbirth preference, b = 6.88, 95 % CI, t(419) = 4.38, p < 0.001, however the relationship was weakened. The indirect effects of childbirth fear and self-efficacy expectancy were significant  on childbirth preference, childbirth fear, and childbirth self-efficacy in nulligravid women, and whether childbirth fear and childbirth self-efficacy (outcome expectancy and self-efficacy expectancy) mediated changes in childbirth preference. As expected, in positively evaluated birth stories, childbirth preference shifted towards the described method. In negatively evaluated stories, childbirth preference shifted away from the described method. The changes in childbirth preference significantly differed between all conditions except for between the positive vaginal and negative caesarean section birth stories, and between positive caesarean birth and negative vaginal birth stories. Childbirth fear and self-efficacy expectancy partially mediated the effect of the stories on childbirth preference. However, contrary to expectations, the outcome expectancy component of self-efficacy did not mediate the relationship between birth story exposure and childbirth preference arising from any variations in storyteller evaluation or type of birth. Additionally, childbirth self-efficacy and childbirth fear were not found to mediate the influence of caesarean birth stories on childbirth preference.While the type of birth endorsed in the birth stories influenced the direction changes in childbirth preference, it was the combination of type of birth and storyteller evaluation that triggered the change. Neither evaluation nor type of birth had a stronger effect on childbirth preference. Even this brief exposure to birth stories influenced the childbirth preference of nulligravid women irrespective of the type of birth and the storyteller’s evaluation. As such, social and cultural influences shared through birth stories have the potential to perpetuate or minimise views of childbirth as a medicalised or non-medicalised process in the next generation of childbearing women.It was hypothesised that childbirth self-efficacy and childbirth fear would mediate the effect of birth stories on childbirth preference. In contrast, only exposure to vaginal birth stories resulted in a change in childbirth fear and self-efficacy that was associated with changes in childbirth preference. As expected, exposure to positive vaginal birth stories led to a decrease in childbirth fear and increase in both scales of self-efficacy, however, the magnitude of the increase in outcome expectancy was small. Conversely, negative vaginal birth stories increased childbirth fear and decreased both scales of self-efficacy. In turn, childbirth fear and self-efficacy expectancy led to an increase in vaginal birth preference, but outcome expectancy did not. Therefore, change in childbirth preference generated by vaginal birth stories was partially mediated by childbirth fear and self-efficacy expectancy, but not by outcome expectancy.Previous research reported lower levels of outcome expectancy in women who prefer caesarean birth . HoweverOverall, caesarean birth stories resulted in little to no change in childbirth fear, outcome expectancy, and self-efficacy expectancy, and change in childbirth preference elicited by caesarean birth stories was not mediated by changes in childbirth fear or childbirth self-efficacy. In the current study, childbirth fear and childbirth self-efficacy were operationalised as fear of, and self-efficacy for, vaginal birth. Consequently, it is possible that the stories influenced other psychological factors specific to caesarean birth or that the influence of experiential features of caesarean birth stories were not transferred to the context of a vaginal birth experience.This study is the first to experimentally assess the effect of birth stories on childbirth preference in nulligravid women and to consider childbirth fear and self-efficacy as explanatory psychological factors in this relationship. The final sample was of substantial size and was not limited to younger women, therefore reflecting the broader views of women that have not yet given birth. A caveat to the population representativeness was that most participating women had completed university education. Women with lower socio economic status and lower education levels are more likely to be influenced by people and media, and more likely to lack knowledge about caesarean birth indications . ConsequAlthough using established scales to measure childbirth fear and self-efficacy maximised validity, reliability, and comparability with other research, the imposed survey length may have resulted in the loss of participants at the time of the post-exposure measures of childbirth fear and self-efficacy. The potential biases in participant loss that may have been associated with demographic characteristics could not be determined because these were assessed at the end of the survey. As these scales were designed specifically for vaginal birth, equivalent scales for caesarean birth are needed to assess the role of fear and self-efficacy for determining childbirth preference more accurately.The use of a continuous measure of childbirth preference provided greater sensitivity to smaller changes in childbirth preference than an alternative dichotomous measure. However, this was at the sacrifice of ecological validity. Ultimately, there are only two options for childbirth, vaginal or caesarean birth, and thus the extent to which women’s expressed childbirth preferences reflect future childbirth decisions or outcomes remains unknown. Finally, the design of this study did not allow examination of whether the effect of the stories was short lived or long lasting, or whether the effect of stories in one category could be counteracted by another (as might be assessed in a crossover design).The current study showed women’s childbirth preferences were affected by birth stories even though they were not yet pregnant and consequently not faced with making a deliberate choice about type of birth. This finding is striking given the incidence of positively evaluated planned caesarean birth stories in modern society may only increase in the future alongside the ever-increasing use of caesarean birth, and considering that most women who undergo planned caesarean birth are satisfied . In addimay benefit from medical assistance. Future research should aim to evaluate the effect of such programs on fear, self-efficacy, and childbirth preference and to assess how birth stories can be effectively used to enhance program delivery and impact.Understanding the influence of vicarious experience on childbirth preference and the psychological mechanisms at play is not about attributing values to one method of childbirth over the other, but to ensure that women make decisions that are informed by unbiased information and not driven by fear or lack of self-efficacy. Women are more likely to experience post-traumatic stress symptoms when they have a childbirth that differed from their preference than when they experience the type of birth they preferred . TherefoGlobally, the rate of nulligravid women who express a preference for caesarean birth without medical indications already surpasses the WHO recommended rate for caesarean birth. Caesarean birth preference is accompanied by higher childbirth fear and lower self-efficacy. The current study showed that this preference is influenced by vicarious experience in the form of birth stories, alongside childbirth fear and self-efficacy. Negative vaginal and positive caesarean birth stories, which reflect those that women are most likely to encounter online and in social and public media, led to an increased preference for caesarean birth. This study offers preliminary evidence for the psychological mechanisms underpinning the relationship between vicarious experience and childbirth preference. It highlights the potential utility of educational programs that address childbirth fear and increase self-efficacy, and support childbirth decision-making best reflects individual needs.Additional file 1.Additional file 2.Additional file 3.Additional file 4.Additional file 5.Additional file 6.Additional file 7.