Expectant parents worldwide have experienced changes in the way they give birth as a result of COVID-19, including restrictions relating to access to birthing units and the presence of birthing partners during the birth, and changes to birth plans. This paper reports the experiences of women in England.n = 477 families) between 15th July 2020 – 29th March 2021. Frequency data are presented alongside the results of a sentiment analysis; the open-ended data was analysed thematically.Data were obtained from both closed- and open-ended responses collected as part of the national COVID in Context of Pregnancy, Infancy and Parenting (CoCoPIP) Study online survey  (66.1%) and a third via caesarean section (CS) (32.6%) or ‘other’ (1.3%). Just under half (49.7%) of the CS were reported to have been elective/planned, with 47.7% being emergencies. A third (37.4%) of participants reported having no changes to their birth (as set out in their birthing plan), with a further 25% reporting COVID-related changes, and 37.4% reporting non-COVID related changes . One quarter of the sample reported COVID-related changes to their birth plan, including limited birthing options and reduced feelings of control; difficulties accessing pain-relief and assistance, and feelings of distress and anxiety. Under half of the respondents reported not knowing whether there could be someone present at the birth (44.8%), with 2.3% of respondents reporting no birthing partner being present due to COVID-related restrictions. Parental experiences of communication and advice provided by the hospital prior to delivery were mixed, with significant stress and anxiety being reported in relation to both the fluctuating guidance and lack of certainty regarding the presence of birthing partners at the birth. The sentiment analysis revealed that participant experiences of giving birth during the pandemic were predominately negative (46.9%) particularly in relation to the first national lockdown, with a smaller proportion of positive (33.2%) and neutral responses (19.9%).The proportion of parents reporting birthing interventions  was higher than previously reported, as were uncertainties related to the birth, and poor communication, leading to increased feelings of anxiety and high levels of negative emotions. The implications of these findings are discussed. In January 2020 the first case of COVID-19 in the UK was confirmed  and on tThroughout the pandemic, pregnancy and childbirth have been associated with anxiety and uncertainty for many pregnant women and their partners due in part to the changing landscape of the healthcare system and increased demands on healthcare providers , 16, 17.In the UK, government guidelines aimed at curbing the spread of the virus also led to a number of suboptimal conditions for expectant parents giving birth. In March 2020, National Health Service (NHS) trusts began to suspend home birth services and support in response to the COVID-19 outbreak . This waFrom the beginning of the pandemic, individual NHS trusts were required to draw up their own guidance with regard to access to maternity services and birth partners, based on government guidelines. The restrictions made were underpinned by considerations of public health and the prevention measures necessary to curb infection rates. Most commonly, the guidance stated that partners were only allowed to be present when the mother was 4 cm dilated, that they were not allowed to be present at the start of an induction and were not allowed to join their partners during the pre-operation preparation for a caesarean section (CS); and that they were to leave shortly after the birth . A surveOn the 8th September 2020, NHS England issued guidance to individual NHS trusts “to reintroduce access for partners, visitors and other supporters of pregnant women in English maternity services” . HoweverThe CoCoPIP Study was developed to explore how COVID-19 and the cascade of changes in healthcare, social restrictions and government guidance impacted the lives of families who were expecting a baby or had recently given birth , 5. Prevn = 477, see Table Survey data was taken from the period 15th July 2020 – 29th March 2021 . For the full survey, response time was ~ 30 min and respondents were included in a £100 gift card prize draw . As Descriptive data is presented below in the form of frequencies. Quantitative analysis of the data involved a sentiment analysis to give researchers an overall understanding of the parents’ perceptions about their emotional state during this time. As with previous research , 5, thisFor the thematic analysis, the qualitative data was imported from Qualtrics® via Redcap®  into NViThe coding trail was double checked by EA. Finally, confirmability was addressed by ensuring a clear presentation of participant responses, and by providing a clear rationale for each step involved in the methods and analysis; furthermore, an additional researcher (KAG) conducted a reliability analysis of 25% of the data to confirm the themes and sub-themes identified. It is important to note that any data reported as occurring ‘as a direct result of COVID-19 only’ includes answers where the individual explicitly referenced ‘COVID’, ‘pandemic’ or ‘PPE use’ in their response to the semi-structured questions asked  and second (EA) reviewers are academics involved in social policy and pre- to postnatal development, and third (KAG) reviewer has a background in educational qualitative research analysis meaning we approached this review and meta-synthesis with an interdisciplinary lens.Of the 477 participants who responded to questions regarding their birthing experiences during the pandemic, a third completed the survey during one of the three national lockdowns 39.5%, 188), around half completed the survey during the period of easing of restrictions  and a small percentage were completed during the introduction of a tiered system   , a third delivered via CS 32.6%, 155), and ‘other’  . Of the 155 participants who reported giving birth by CS, just under half  reported having an elective/planned CS, with the remainder  having an emergency CS (4 participants did not report on whether their CS was an elective or emergency procedure) , and a fifth reported that they were unaware prior to the birth whether birthing partners would be allowed to be present  , 33.2% expressed positive, 19.9% neutral and 46.9% negative sentiments. When observing sentiment in relation to the governmental guidance and restrictions  reported no changes to their planned birth , 25% (115) reported changes to the planned birth due to COVID and 37.4% (172) reported changes due to other reasons . Parents’ experiences of the COVID-related changes are described below:Of the 462 respondents who responded to the question ‘‘My birthing experience was exactly how I'd planned/hoped. I had a very basic idea of how I'd like to give birth but was very open to other options. I was lucky enough to have a straight forward water birth with no complication’And‘It was the way I wanted to. The birth experience was the most normal thing in the whole pregnancy’Although many parents across the UK experienced difficulties and hardships whilst giving birth, some respondents to the survey reported their birthing experience going according to their birthing plan, with parents recalling positive experiences in relation to the birth of their child:‘…. My birth plan was followed in that I was able to do and use the things I wanted and the staff knew that I was flexible should I need to be dependent on the situation that arose at the time.’Another participant referred to additional support offered due to previous birthing trauma:‘Went exactly has[sic] planned and everyone was very calm and friendly due to previous birth trauma the year before.’However, a number of participants stated that there were no changes because birthing plans were not being made during national restrictions:‘I was informed by my midwife that they were not making birthing plans during lockdown so I didn't have a plan.’While this was experienced well by some women -‘I had no birth plan so it all went how I would of liked it’- other statements suggest that some women felt less clear about the impact of this:‘I didn't really make a birth plan, my labour was led completely [b]y the midwife at the time. I decided it was best to go with the flow and not really make a plan. It was slow and long which ended in an emergency caesarean.’Some participants described feeling supported and informed at the time of giving birth:‘Planned home water birth. All home births cancelled. All water births cancelled’‘Big changes. I was induced, had an epidural [….], where I had wanted a water birth. My husband wasn't allowed to attend until my waters had been manually burst, which did influence me to say yes so that he could join me.’‘Husband unable to attend induction or stay with baby & I after birth. Rushed hospital discharge, no visitors, PPE used by staff & I had to wear it whilst in labour too.This respondent went on to describe the feeling of being rushed and of having no control:Felt impersonal, rushed, somewhat out of control & birth options v limited (no access to birth centre or home birth). V[sic] different to what we had planned!’A number of respondents described being alone, and in one case, the cancellation of plans that had been developed to help prevent the reoccurrence of her postnatal depression:‘No one read my birth plan. I was alone for the majority of my labour. My birth partner was only allowed to join me right at the end.’‘I was alone throughout the birthing experience. I couldn't have a water birth, couldn't have visitors. Most things planned to help reduce the reoccurrence of postnatal depression could not be put into place.’One respondent reported having trouble accessing the desired pain relief and assistance during her labour:‘It changed I was induced due to potential infection. And was unable to have the desired pain relief and staffing was low, and they didn't arrive in my very quick labour’These changes and restrictions resulted in some parents feeling considerable distress and anxiety:‘I wasn't allowed the birth I wanted because of covid. It was hugely traumatic […]’One of the most notable COVID-related changes reported was the suspension of home births and birthing pools:‘I was induced due to potential infection’) women reported feelings of anxiety and distress with regard to these changes due to the lack of support and communication offered by hospitals:‘My birth plan changed as the baby was in a difficult position but as I was the last in my pregnancy group to give birth and 5/7 of them had had a c-section I was very worried I would have to have a c-section. In hospital it felt like it was my only option’These feelings were further exacerbated as a result of COVID-related restrictions to birthing support:‘I would have like[d] a natural labour but my body didn't go into labour. I suffered from PTSD from my [eldest’s] birth where I was induced therefore it was advised I shouldn't be induced again. I spent a lot of time worrying about a situation where I might have had to be induced without my husband’s support’.Some respondents who described changes to their birth appeared to adapt well to the changes as a result of feeling supported and informed throughout their journey:‘Things did not go to plan, but I was kept informed, I was consulted on actions taken and my birth plan was considered throughout.’‘Change of plan but staff in operation was amazing’.Overall it is evident from the above responses that during the first year of the pandemic mixed experiences were had by parents, with almost equal numbers of participants reporting, COVID-related and non-COVID related changes to their birthing plans. To gain a better overview of participants experiences during childbirth, we asked also parents to reflect on the communication they had received from medical staff and/or the hospital prior to the birth of their baby regarding access to birthing partners during the delivery. We identified three key themes related to responses to this question (see Table n = 250): (1) Communication, (2) Impact of fluctuating COVID-related guidance, (3) Anxiety and stress related to changing guidance.Whilst changes to delivery can be expected when giving birth  across lockdown conditions and coded the themes expressed by parents’ open-ended responses, as well as describing the type of delivery, the presence of birthing partners, and changes in birth plan reported by our sample. To date, our study provides the largest sentiment analysis of birth experiences in the UK [Our results show that 32.6% of participants reported having a CS, of which 49.7% were elective. This represents a significant increase relative to pre-pandemic levels throughout the year of 2019-20 where whilst one-third of deliveries were also typically CS, elective CS were 7% less , demonstrating uncertainty around access to birth partners throughout a year of the pandemic. When asked to elaborate on how this communication (or lack of) from the hospital made expectant mothers feel  reports of negative birth experiences , 34. In Results from our thematic analysis support those of a survey conducted by Mumsnet and Birthrights between December 2019 – September 2020, which found that many women reported that their decisions with regard to childbirth  were not respected with many reporting their choice was either not considered or disregarded [The findings also suggest, however, that whilst changes to the birth were experienced by a large proportion of our sample, clear communication and support appeared to mitigate these negative childbirth experiences. These findings are consistent with the wider recognition that women’s feelings and ability to exert choice and control during the birth, are more important in terms of long-term wellbeing, than the objective facts of the birth . It is aAs data were collected between July 2020 – March 2021, participants’ experiences reflect a period of fluctuating COVID-related government and healthcare restrictions, from the most severe national lockdown measures to a combination of severe to mild national/local restrictions. Due to the rapidly evolving nature of the governmental guidance related to the pandemic and regional variations in between national lockdowns it, was not possible to collect equal sample sizes at each timepoint. Furthermore, as a result of the fact that this study was conducted as a voluntary online survey, we cannot confirm independently that all responses were by expectant parents or exclude bias in respondents with either positive or negative experience of giving birth. Whilst we advertised this study nationally and specifically worked with national childbirth trusts (NCTs) with an emphasis on areas of low socio-economic status (SES), the majority of participants were white; therefore, the results cannot be generalised to a more ethnically diverse population. This study is part of an ongoing longitudinal study observing the impact of COVID-19 on pregnancy, infant development and parental mental health and we hope we increase the diversity of our sample as recruitment continues. Another limitation is that, of the two questions posed, not every participant gave a response to each one. Finally, in terms of the qualitiative data, the fact that it was collected using a survey, meant that it was not possible to probe further in terms of whether detailed guidance given by the trust could have influenced the birth accounts and contributed to the specific reasoning behind the change in birth plan.The mitigation measures implemented by the government and the NHS throughout the COVID-19 pandemic have had a significant secondary impact on expectant women and families. Whilst changes to the birth plan due to COVID were experienced by a large proportion of our sample, the qualitative data suggest that clear communication and support appeared to mitigate these negative childbirth experiences. This should include allowances for choice of birthing methods as well as the availability of consistent support for the duration of the labour and birth.Further research is needed to explore the impact of variation in birth experiences, both on maternal mental health in the postpartum period , on mateChanges to birth experiences and offered support - in response to governmental guidance with regard to mitigating the spread of the virus and the increased burden on the healthcare system - has had an adverse effect on the experiences of many pregnant women and their partners in England. Whilst restrictions were aimed at balancing population- based harm and individual liberities, it is apparent this balance wasn’t always struck. These findings reinforce the importance of the role of choice and control in women’s childbirth experience, as well as clear communication from healthcare providers. In addition, the findings demonstrate the need to ensure consistent guidance and support to better address the unique health care needs of each pregnant woman in any future lockdowns, as well as the need to observe the potential long-term impact on their offspring.


Premature infants born after less than 25 weeks’ gestation are particularly vulnerable at birth and stabilization in the delivery room (DR) is challenging. After birth, infants born after <25 weeks’ gestation develop respiratory and hemodynamic instability due to their immature physiology and anatomy. Successful stabilization at birth has the potential to reduce morbidities and mortalities, while suboptimal DR care could increase long-term sequelae. This article reviews current neonatal resuscitation guidelines and addresses challenges during DR stabilization in extremely premature infants born after <25 weeks’ gestation at the threshold of viability. The impending birth of periviable infants born after 22 + 0 to 24 + 6 weeks’ gestation is associated with anxiety and uncertainty for family members and healthcare teams . ParentaIn recent decades, gestational age has continuously shifted lower. However, the stabilization of premature infants born after <25 weeks’ gestation in the DR remains challenging . The curDecision making about active or comfort  care in infants to be delivered between 22 + 0 to 24 + 6 weeks’ gestation is challenging. Gestational age  is used as the main determinant for decision-making due to its association with outcomes ,9. CurreSurvival rates among periviable infants born after 22 + 0 to 24 + 6 weeks’ gestation increase for deliveries that occur in hospitals with NICUs that have both a high level of care and a high volume of such patients . Differep = 0.23) [Immediate cord clamping (ICC) has been used for several decades. However, evidence suggests that ICC might cause an acute reduction in left atrial filling, leading to an abrupt drop in left ventricular output . In cont = 0.23) . While t = 0.23) ,5,6.p = 0.031) and language composite score  at 22–26 months of corrected age compared with those randomized to DCC [p = 0.02) [Intact umbilical cord milking (I-UCM) has been advocated as an alternative to DCC, particularly in infants who do not breathe at birth . Animal d to DCC . HoweverAn alternative approach of umbilical cord milking is cut-umbilical cord milking (C-UCM), which is performed by early cord clamping and retaining a long segment of the umbilical cord that then can be milked while initiating ventilation . In extrAnimal models demonstrated that hemodynamic transition improves when respiratory support is provided while preterm lambs remain attached to the cord . Randomized trials have compared intact cord resuscitation with ECC , DCC 3131,32, orThermal care to maintain body temperature between 36.5 and 37.5 °C is crucial to reduce morbidity and mortality in premature infants . AdmissiApproximately 80% of ELBW infants initiate spontaneous breathing at birth. However, all of them require CPAP and/or PPV after birth due to their weak respiratory drive, low respiratory muscle strength and lung immaturity . The prep < 0.001) in late premature infants [2), but did not result in differences in respiratory effort between groups [Tactile maneuvers might stimulate breathing and thereby improve oxygenation in premature infants ,46,47. Kn groups .Another strategy to improve the breathing effort after birth in premature infants is the postnatal administration of intravenous caffeine. Caffeine administration was associated with increased diaphragmatic activity and tidal volume within five minutes of its administration in infants born between 26 and 34 weeks’ gestation . A rando2 of 1.0 versus 0.3 and reported significantly higher breathing efforts, improved oxygenation, and a shorter duration of PPV with a FiO2 of 1.0, while an increased risk of hyperoxemia or oxidative stress was not observed [2 resulted in improved tonic diaphragmatic activity [2 as discussed in More controversial might be the effect of oxygen on the initiation of spontaneous breathing in premature infants . A randoobserved . Additioactivity . This stactivity ,5,6,7 reOropharyngeal or nasopharyngeal suctioning immediately after birth may delay the onset of spontaneous breathing, and therefore, should only be considered in the case of visible airway obstruction ,52. SuctThe presence of spontaneous breathing after birth has an enormous effect on successful lung aeration and on the establishment of functional residual capacity ,45. It c2O [2O might be too low to effectively recruit the lungs in extremely premature infants [The goal of respiratory support in the DR is to create a functional residual capacity, establish gas exchange, and initiate spontaneous breathing while minimizing acute lung injury . Current2O ,5,6. How infants ,54,55 du infants ,57,58. T infants .p < 0.001) [p = 0.70) [During respiratory support, applying a face mask might induce a trigeminocardiac reflex provoking apnoea and bradycardia in a large proportion (54%) of premature infants . This ma< 0.001) . Applyin = 0.70) ,62.In addition to face masks and bi-nasal prongs, nasal tubes might be equivalent alternative interfaces for PPV at birth in ELBW infants . Other sPremature infants are highly susceptible to oxygen toxicity due to a deficient anti-oxidative capacity, exacerbating morbidities such as bronchopulmonary dysplasia (BPD), retinopathy of prematurity, IVH and necrotizing enterocolitis ,67. Alte2 of 0.21–0.3 [2 to initiate respiratory support in those patients after birth remains a hot topic for future research [A meta-analysis of seven trials  in premature infants born after ≤28 weeks’ gestation reported no differences in mortality, major morbidity, or neurodevelopmental outcomes when respiratory support was started with low (0.21–0.3) compared with higher oxygen 0.6–1) . Recent 0.21–0.3  or 0.3 [0.21–0.3 ,6 for pr–1 . Receresearch . In part2 adjustments should be guided by pulse oximetry. Oxygen titration should be attempted every 30 s to meet predefined oxygen saturation targets [During postnatal stabilization, FiO targets . Not ach targets . A meta- targets . It rema targets ,72.2O via either a face mask or nasal prongs rather than endotracheal intubation and mechanical ventilation [Spontaneously breathing premature infants demonstrating respiratory distress should receive respiratory support by continuous positive airway pressure (CPAP) with at least 5–6 cmHtilation ,6,73,74.tilation  includedtilation .2O) compared to 5 cmH2O resulted in higher pulmonary blood flow levels when applied from birth, without causing pulmonary overexpansion, cardiovascular compromise or increased risk for IVH [2O at ~2 cmH2O/min) which takes into account the changes in lung function during stabilization in the DR [The optimal CPAP levels for initiating respiratory support in the DR in spontaneously breathing premature infants born after <25 weeks’ gestation should be addressed in future trials. Interestingly, a recent animal study has shown that higher initial CPAP levels  period of PPV, and subsequent early extubation . INSURE,Endotracheal intubation and the subsequent invasive ventilation should be reserved for premature infants not responding to PPV during DR stabilization, and they should then receive surfactant via the endotracheal tube .None of the international resuscitation guidelines endorse withholding chest compressions and/or epinephrine administration from the subgroup of premature infants born after <25 weeks’ gestation ,7, althoThe current neonatal resuscitation guidelines recommend vascular access if infants require chest compressions or fluid administration . VasculaMore recently, intraosseous access has been advocated as an alternative to umbilical venous catheterization . A totalOnce the decision to provide full life support in premature infants born after <25 weeks’ gestation is made, the active management of such infants remains challenging due to the fact that evidence for periviable neonates is lacking and guidelines are mainly based on expert consensus, physiologic plausibility, as well as data derived from more mature low-gestational-age infants. In recent years, there has been growing evidence for providing gentle, less invasive support in the DR to reduce mortality and short- and long-term morbidities. Further research into all the aspects of stabilization and resuscitation focusing on the subgroup of premature infants born <25 weeks’ gestation is urgently warranted.


This systematic review and meta-analysis investigates visual attention functioning during the first 2 years of life in infants born preterm versus full term. Is preterm birth associated with visual attention impairments in early life, and if so, in which attention functions?This systematic review and meta-analysis of 53 studies including 2047 preterm-born and 1951 full-term–born neonates and infants found that preterm birth was significantly associated with impairments in visual attention functioning. Despite a short-term advantage in visual-following in preterm infants, deficits cascaded from basic orienting responses to focused attention during the first 2 years of life.The findings suggest that preterm birth is associated with challenges in the development of visual attention beginning in the early stages of life. Preterm birth is associated with an increased risk for long-lasting attention deficits. Early-life markers of attention abnormalities have not been established to date but could provide insights into the pathogenesis of attention abnormalities and could help identify susceptible individuals.To examine whether preterm birth is associated with visual attention impairments in early life, and if so, in which attention functions and at which developmental period during the first 2 years of life.PubMed and PsycINFO were searched on November 17, 2019, to identify studies involving visual attention outcomes in infants born preterm vs full term.Peer-reviewed studies from the past 50 years met the eligibility criteria if they directly assessed visual attention outcomes until the age of 2 years in generally healthy infants born preterm or full term. The selection process was conducted by 2 independent reviewers.The Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline was followed. Random-effects models were used to determine standardized mean differences. The risk of bias was assessed both within and between studies.Five nascent indices of visual attention were analyzed, including very basic functions—namely, the abilities to follow and fixate on visual targets—and more complex functions, such as visual processing , recognition memory , and the ability to effortfully focus attention for learning.d, −0.77; 95% CI, −1.23 to −0.31), latency to fixate , novelty preference , and focused attention . In the neonatal period, preterm birth was associated with superior visual-following , possibly owing to the additional extrauterine exposure to sensory stimulation. However, this early association waned rapidly in infancy .A total of 53 studies were included, with 69 effect sizes and assessing a total of 3998 infants . Preterm birth was associated with impairments in various attention indices, including visual-following in infancy (Cohen The findings suggest that preterm birth is associated with impingements to visual attention development in early life, as manifested in basic and then complex forms of attention. Advancements in neonatal care may underlie improvements found in the current era and accentuate several early protective factors. Advancements in obstetrics and neonatal care have been associated with an increase in preterm births worldwide,2 which account for 10.6% of live births.3 Despite the positive aspects of better survival and care, preterm birth has implications for learning,4 cognitive performance,6 and attention5; deficits in these areas may underlie the association of preterm birth with poorer quality of life7 and substantial economic costs.9Preterm birth, a live birth before gestational age (GA) of 37 weeks,11 which is a pivotal period for attention development involving the progression from basic abilities that are highly reactive and dependent on external cues12 to an initial exertion of volitionally channeled attention.13 It is important to understand how a congenital vulnerability  affects this expected developmental course. Neurodevelopmental frameworks advocate a model that traces the long-term cognitive sequelae of preterm birth to the cascading implications of early dysfunctions in regulatory and attentional facets.16 This approach accentuates the idea that the emerging operations of higher cortical loci, which are later to materialize from both the phylogenetic and the ontogenetic perspectives, are influenced by earlier dysregulation of midbrain structures,18 thus compromising the distributed attentional networks further as the child matures.21 The stage-specific behavioral-attention expressions of this cascade are not yet fully mapped.Susceptibility to these long-term deficits may manifest during the first 2 years of life,22 Younger GA at birth is associated with diminished myelinogenesis,23 synaptogenesis, and dendritic sprouting.24 Extrauterine exposure to sensory stimulation in premature neonates exposes the underdeveloped neural network to stressors, resulting in augmented sensitivity26; this marks the neonatal period as a supersensitive period for attention development. Thus, reviewing the formation of notable attention functions in the early life of infants born preterm may reveal factors needing consideration.The third trimester of pregnancy is a period of rapid neural growth for the fetus.27 and follow salient visual stimuli.28 These faculties further develop during the first year of life.29 After the transition from reliance on brainstem-basilar–mediated pathways to the increasing involvement of cortical structures in the second year of life, infants exert more endogenous direction over visuospatial attention.13 This is expressed by 2 notable abilities that predict intellectual performance in later childhood in both the typically developing and the preterm-born populations11: first, novelty preference ,12 and then focused attention .30Basic attention faculties, typically available in the neonatal period, include the ability to fixate on salient cues in the periphery of the visual field21 Vis-à-vis the implications of early extrauterine exposure to sensory stimulation, it is possible that during the first weeks of life, preterm infants will nevertheless benefit in precocial attention abilities resulting from the additional exercise of the visual system.29 However, it is conjectured that this early advantage at term age will rapidly wane, because the burden of premature stimulation and activation of attention networks will be associated with durable deficits in attention tasks from early infancy onward.29 To assess these hypotheses, a concise review of the literature is required.To date, it remains unclear whether preterm birth triggers a negative cascading effect on attention development and how it affects each essential attention function in early life. Based on the cascade assertion, it is expected that deficits in more basic functions such as following and latency to fixate on visual stimuli will be evident in early developmental stages and might ebb in later stages; regarding endogenous attention functions such as novelty preference and focused attention, it is expected that earlier neurophysiological dysregulation will lead to long-lasting deficits.82 Two notable reviews84 from previous decades suggested that infants born preterm show less-optimal attention performance. However, because both reviews were nonsystematic and did not attempt a statistical synthesis, there was a necessity for a methodical review to revisit the important claims of the previous studies while assigning distinct emphasis to each of the focal-attention faculties.During the past 50 years, a myriad of studies assessed the association between preterm birth and attention development in early life, but only a few reviews attempted to synthesize and generalize the findings.We expected that the developmental course would be significantly associated with preterm birth in ways that cascade from basic to more endogenous forms of attention. The aim of this study was to examine which attention faculties might benefit from early extrauterine exposure to stimuli and which might be compromised as the preterm-born infant experiences increasing attentional demands. In addition, we aimed to assess whether the substantial advancements in neonatal care were also associated with ameliorations in attention development.MOOSE) reporting guideline.85In this systematic review and meta-analysis, we reviewed the literature to identify studies involving visual attention outcomes in infants born preterm vs full term. This study followed the Meta-analysis of Observational Studies in Epidemiology (The eligibility criteria for included studies were (1) publication in a peer-reviewed scientific journal or book, (2) publication during the past 50 years, (3) inclusion of both a preterm  and a full-term group, (4) inclusion of infants aged 2 years or younger, (5) inclusion of healthy participants , and (6) reporting of at least 1 visual attention measure that had been directly attained from testing the participant .preterm OR premature OR pre-term OR prematurity] AND attention AND [(infant OR infants OR infancy) OR  OR (toddler OR toddlers OR toddlerhood)]. Further records were identified by manual review of studies’ references.The literature review was conducted November 17, 2019, in the PubMed and PsycINFO databases using combinations of the following keywords: ; I2, 58.3%). A difference in effect sizes was found  between studies that used real-time observers’ coding of gaze  and those that used computerized gaze tracking . These findings suggest a quantitative interaction, with a more robust difference between the groups when computerized equipment was used (plausibly owing to increased tracking sensitivity).No evidence of heterogeneity was found in the studies of neonates, but an indication of heterogeneity was found in the studies of infants . There was no evidence of heterogeneity. However, a moderation analysis indicated that birth era was associated with the differences , suggesting an increased risk for deficits in preterm cohorts of infants born before 1990 and who are now at least 30 years of age  and novelty preference  are theoretically intertwined because both reflect gaining familiarity with the stimulus through inspection. Both constructs were, therefore, considered in this review, and the association between them was analyzed .59 with 13 effect sizes were included. No differences were found between the groups in habituation . There was no evidence of heterogeneity. However, a moderation analysis indicated that birth era was associated with the differences , suggesting an increased risk for deficits in preterm infants born before the year 2000 and who are now in their 20s . There was no evidence of heterogeneity.For the meta-analysis of novelty preference, 15 eligible studiesP = .32).To assess whether differences in habituation are associated with the extent of differences in novelty preference, we explored the 10 populations for whom both measures were reported. The analysis showed no association . There was evidence of heterogeneity , indicating that a moderate portion of the variance was explained by heterogeneity rather than chance . The heterogeneity was explained by 2 outlier findings; their removal attenuated the effect size but did not annul it , suggesting that the increased risk for focused-attention deficits after extremely preterm birth was attenuated in cohorts born after 2000 but did not completely ebb  were more likely to experience difficulties compared with typically developing infants born at full term.96 and at preterm5 might already be discernible in infancy.To our knowledge, this is the first systematic review and meta-analysis of preterm birth and the development of visual attention during infancy. Considering findings from 53 studies including 3998 infants, this review revealed that individuals born preterm had greater likelihood of attention difficulties as early as during the first 2 years of life. Increased likelihood for impairments cascaded from more reflexive functions—namely, visual-following  and latency to fixate—to more endogenous forms of attention, such as visual recognition memory (as expressed by novelty preference but not by habituation), and was most apparent in focused attention. The current findings support findings from previous studies suggesting that the antecedents for the increased risk for diagnosis of attention deficit hyperactivity disorder and learning disabilities in individuals who were born at term97 Neonates born preterm were more likely to show an advantage in visual-following. It has been suggested that exposure to sensory stimulation after preterm birth might prime basic visual attention abilities.29 This claim is corroborated by the findings of this analysis. Preterm birth was associated with superior following even in a study of a population of extremely premature neonates with birthweight less than 901 g.31 An additional analysis . This finding complements the notion that preterm birth is associated with impeded development of endogenous attention throughout adolescence and adulthood.112 and included the implementation of antenatal corticosteroid and postnatal surfactant treatments to diminish the risks for respiratory distress, brain damage, and mortality. The second was related to tailored sensorimotor stimulation, nurturance, and physio-emotional and social care during the neonatal stay and is manifested in excitation reduction, physical proximity to caregivers, and breastfeeding facilitation techniques.114 This analysis suggests that attention development during infancy may be sensitive to better-regulated oxygenation and well-titrated stimulation and that advancements in neonatal care may underlie the associated improvements in attention development by preventing overstimulation of posterior orienting and thereafter providing a stronger basis for the development of anterior executive attention networks.115 However, despite the positive trajectory, increased risk for early-life impairments in focused attention after extremely preterm birth still exists in the current era, suggesting that advancements in neonatal care may have enabled better prospects but that there is still more work to be done.The most promising finding from the present review in this regard involved signs that improvements in care and age-sensitive exposure were associated with attention outcomes. The current findings revealed a partial amelioration in focused-attention difficulties as a function of birth era and the accompanied revisions in care protocols . Two majThe findings support the notion that early development of attention skills may be sensitive to stimulation and care in ways that might merit future research: (1) extrauterine exposure to sensory stimulation may account for the short-term association with the precocial establishment of visual-following at term age, and (2) refinement of neonatal and pediatric care in the past 5 decades has improved remarkably in providing individually tailored medical, pharmacological, sensorimotor, emotional, thermal-physical, and social care. The findings of this review suggest that increased risk for deficits in volitional control over visual attention is associated with prematurity (and more pronouncedly with extreme prematurity). Advancements in care, mostly in the current era, seem to underlie a partial remission. Future developments in care during early infancy may support the ability of infants born preterm to focus attention to learn and fulfill their potential.116This study has limitations. First, a demographic bias resulting from overrepresentation of studies from Western Europe and North America (49 of the 53 included studies [92.3%]) curtailed the ecological validity of the findings vis-à-vis other nonrepresented populations. Second, some studies were missing information regarding central covariates . Reporting an adequate set of important background, demographic, and medical characteristics will likely improve the validity of future systematic reviews and deepen the understanding of the mechanisms involved.117 Adherence to acknowledged reporting guidelines may constrain this limitation in the future.119A third limitation was a lack of consistent reporting guidelines and the inaccessibility of data. When conducting an extensive literature review, attempts to reach authors in cases of insufficient data for calculation of effect sizes are not always successful. Most of the lost evidence in this review was from studies conducted in the 1970s, when there was less consensus on reporting guidelines.This systematic review and meta-analysis found that infants born preterm had increased risk for deficits in visual attention, cascading from basic reflexive functions  to difficulties in early operations of endogenous attention, such as novelty preference and focused attention, which are vital for learning about the world. The deficits were more pronounced in infants born extremely preterm. Advancements in neonatal care may underlie improvements found in the current era and accentuate several early protective factors.


Premature birth affects the developmental trajectory of the brain during a period of intense maturation with possible lifelong consequences. To better understand the effect of prematurity on brain structure and function, we performed blood‐oxygen‐level dependent (BOLD) and anatomical magnetic resonance imaging (MRI) at 40 weeks of postmenstrual age on 88 newborns with variable gestational age (GA) at birth and no evident radiological alterations. We extracted measures of resting‐state functional connectivity and activity in a set of 90 cortical and subcortical brain regions through the evaluation of BOLD correlations between regions and of fractional amplitude of low‐frequency fluctuation (fALFF) within regions, respectively. Anatomical information was acquired through the assessment of regional volumes. We performed univariate analyses on each metric to examine the association with GA at birth, the spatial distribution of the effects, and the consistency across metrics. Moreover, a data‐driven multivariate analysis  framework exploited the high dimensionality of the data to assess the sensitivity of each metric to the effect of premature birth. Prematurity was associated with bidirectional alterations of functional connectivity and regional volume and, to a lesser extent, of fALFF. Notably, the effects of prematurity on functional connectivity were spatially diffuse, mainly within cortical regions, whereas effects on regional volume and fALFF were more focal, involving subcortical structures. While the two analytical approaches delivered consistent results, the multivariate analysis was more sensitive in capturing the complex pattern of prematurity effects. Future studies might apply multivariate frameworks to identify premature infants at risk of a negative neurodevelopmental outcome. To better understand the effect of prematurity on brain structure and function, we evaluated BOLD and anatomical MRI metrics in a set of 90 cortical and subcortical brain regions of 88 newborns at 40 weeks of postmenstrual age, with no evident radiological alterations and variable gestational age (GA) at birth. Data‐driven multivariate analyses of these measures were in agreement with univariate findings and indicated that GA at birth was associated with bidirectional and diffuse alterations of BOLD functional connectivity and more focal alterations of regional volume and BOLD activity . Future studies might successfully apply multivariate frameworks to identify premature infants at risk of a negative neurodevelopmental outcome. However, even in the absence of evident brain lesions at standard radiological imaging, this population is still at high risk of a poor neurodevelopmental outcome  techniques have been used for the investigation of developmental alterations in preterm brains , resting‐state functional connectivity nodal strength (rsFCNS), local activity (fALFF), and regional volume in 90 regions of interest (ROIs) covering the whole brain . Neonates born before 37 weeks of GA were selected based on the following exclusion criteria:Chromosomal abnormality or suspected or proven congenital infection .Neurological abnormalities, including germinal matrix hemorrhage of any grade, cystic periventricular leukomalacia, moderate–severe cerebellar hemorrhage, or lesions in the deep or cortical gray matter.Absent functional MRI.SD = 3.7 weeks), 43/88 patients were female and 15/88 were born at term (>37 weeks of GA at birth). Table Neonates born within or after 37 weeks of GA were selected from a group of consecutive neonates without asphyxia that underwent MRI because of periventricular hyperechogenicity at routine early cranial ultrasound. The neonates did not present signal abnormalities at standard MR sequences and had normal neurologic status at a 12‐month clinical follow‐up. The selection resulted in a group of 88 infants born between 25 and 40 weeks  with a whole‐body SAR below 0.2 W/Kg. At the end of standard clinical MRI sequences, whole‐brain functional images were acquired using a T2*‐weighted, echo‐planar imaging (EPI), FFE axial sequence  with a whole‐body SAR within 0.8 W/kg. The functional scan duration was 4 min and 15 s.MR imaging was performed with a 3 T whole‐body system (Achieva 3.0 T X‐Series) from Philips Healthcare  using an eight‐channel head‐only receiver coil. Participants were fed and then sedated with 0.05 mg oral Midazolam per kilogram of bodyweight immediately before the scans to minimize motion artifacts  with default settings  Infant Atlas  matrices were built by evaluating pairwise associations of BOLD signals in the 90 ROIs while accounting for the contribution of the global signal. Each normalized (z‐scored) ROI's BOLD timecourse was regressed on each other normalized ROI's BOLD timecourse using the normalized average (among the 90 ROIs) BOLD signal as an additional independent variable within a general linear model (GLM) framework  strength. We defined this metric as “resting‐state functional connectivity nodal strength” (rsFCNS). Of note, similar measures have been also referred as “degree centrality” in the literature on graph theory  with the other ROIs according to the formula:rsFCNS was evaluated from the rsFC matrices by computing, for the j2.4.3fALFF was evaluated in each of the 90 ROIs of interest using the tool 3dRSFC  that is directly connected to the extent of regional deformation linking the original template to each subject's anatomy.Simple metrics of local brain structure can be derived in preterm newborns from standard anatomical images using the deformation field that maps each image to a template and vice‐versa . A first analysis was conducted at a whole‐brain level to evaluate the average rsFC, rsFCNS, and fALFF among ROIs, as well as the total ROIs volume . Moreover, 4,005 independent rsFC features, each associated with a pairwise correlation between ROIs, as well as 90 rsFCNS, fALFF, and Volume features, each associated with a single ROI, were regressed against GA at birth.For visualization purposes, and to test the extent of ROI‐based spatial effects of GA at birth, the ROIs were grouped into subcortical (8 ROIs), frontal (34 ROIs), temporal (18 ROIs), parietal (16 ROIs), and occipital (14 ROIs) regions. Cortical ROIs were further subdivided according to their medial or lateral location. Pairwise connections were divided in subcortico‐cortical (N = 688 ) and cortico‐cortical  connections, long‐range (N = 2002) and short‐range (N = 2003) connections  and homotopic (N = 45) and non‐homotopic  connections.The same univariate analyses on rsFC and rsFCNS were also performed using only positive rsFC correlations . Additional control analyses for the effects of motion were performed on the six DVARS motion signal variances  and the number of motion outliers in the BOLD acquisition.2.6A data‐driven multivariate analysis framework was implemented to infer GA at birth from different feature spaces Figure . When anTo account for the large numerosity of independent features   or 1 .For rsFC, the 10‐fold nCV analysis was also performed separately on cortical and subcortical connections, on long‐ and short‐range connections, and on homotopic and non‐homotopic connections. For rsFCNS, fALFF, and Volume, the analysis was also performed separately on subcortical and cortical ROIs. To account for pairwise differences in the numerosity of ROIs, or ROI connections, between groups, the multivariate analyses were performed multiple times on the group with the larger numerosity with a random sampling of ROIs to equalize the number of independent features between groups. Average results for this latter analysis are reported in the results section.In addition, we tested whether combining functional and anatomical information in the inference of GA at birth resulted in a synergistic effect. The rsFCNS was excluded from the analysis since this metric is derived from rsFC and does not encode additional information.Finally, control multivariate analyses were also selectively conducted on positive rsFC correlations and using motion metrics as input variables.2.75 iterations was used. Furthermore, pairwise correlation analyses of the ROI regression weights between the different metrics were performed to evaluate the extent of similarity in the spatial distribution of the effect of prematurity. For this analysis, both the Fisher‐z transforms of correlation and the β‐weights were used.Regarding the univariate analyses, ROI‐based regressions of the different metrics with GA at birth were performed and uncorrected, as well as corrected  . Hence, in this case, z‐scores were computed through a bootstrap approach with 10When using the multivariate analysis as a classifier, the performance was assessed through receiver operating characteristic (ROC) analyses. For comparison, the same analyses were also performed on randomly shuffled labels. The ROC analysis delivered an area under the curve (AUC) which was transformed into a z‐score to test its statistical significance.33.1SD = 5) per subject were deemed as outliers, which where anyhow accounted for during preprocessing.Figure 3.2We here report a summary of the results of the univariate analyses. Please refer to p's > .05) and a rather equal amount of positive and negative correlations were observed between regional or inter‐regional metrics and GA at birth.No global effect was found . Only two connections with the strongest negative correlations survived multiple comparison corrections. Subcortico‐cortical connections had a significantly lower average correlation with GA at birth compared with cortico‐cortical connections . Moreover, long‐range connections had a significantly higher average correlation with GA at birth compared with short‐range connections .For rsFC, the results did not suggest strong focal effects . No specific spatial pattern seemed to emerge, except for stronger medial‐frontal connections in more premature infants .When collapsing rsFC into rsFCNS, no ROI was significantly correlated with GA at birth after multiple comparison correction .fALFF had weak regional univariate associations with GA at birth  and none survived multiple comparison correction . However, when grouping subcortical ROIs, these regions showed increased correlation with GA at birth compared with medial frontal ROIs .Consistent with previous studies looking at the effect of prematurity on regional volume .A significant spatial consistency of the effects across metrics was only observed between fALFF and Volume  approaches. The scatterplot in Figure r = .441, df = 86, p = 1.7 × 10−5, 9 PLS components). The AUC of the classification analysis was 0.825 , in line with previous studies  but only using a classification modality . The analysis of fALFF showed a significant inference of GA at birth  and a significant classification performance . Volume was the metric that reached the highest performance, both in terms of regression  and classification of GA at birth .Figure p = 9.9 × 10−3) and a tendency for a better performance compared with fALFF . The regression performance of Volume was significantly higher than that of rsFCNS  and that of fALFF  and it was higher, but only tended toward statistical significance, than that of rsFC . The statistical comparison of classification performance indicated a higher performance of rsFC compared with rsFCNS  and fALFF . Similarly, significantly higher classification performance was observed for Volume over rsFCNS  and fALFF . No difference was observed between rsFC and Volume and between rsFCNS and fALFF.Figure p = .04) and tended toward significance when controlling for the difference in numerosity between the two subgroups .We then examined the contribution of different subsamples of ROIs in the inference of GA at birth within the multivariate framework. Figure p = 4 × 10−4). However, the difference did not reach statistical significance when controlling for the lower numerosity of the homotopic connections subgroup. Figure p = .01) and Volume . However, differently from rsFC, these effects vanished when accounting for the larger numerosity of the cortical group. Notably, Volume was the only metric that significantly inferred GA at birth using only subcortical regions . No significant difference was found for rsFCNS.Non‐homotopic connections appeared to perform worse than homotopic connections , indicating a substantial concordance in the spatial pattern identified by the two approaches  and fALFF . Volume exhibited the lowest correlation between multivariate and univariate weights .As a further investigation of the spatial distribution of the effects of prematurity on the different metrics, we tested for a significant spatial correlation between regression weights obtained with the multivariate and univariate analyses of the whole data set. Figure df = 86, p = 2.2 × 10−10,10 PLS components) and classification  performance compared with individual metrics (refer to p's > .05).The 10‐fold nCV multivariate analysis combining rsFC, fALFF, and Volume resulted in a slightly higher regression .A control analysis was performed to assess the impact of negative correlations on the results of the analyses on connectivity metrics (rsFC and rsFCNS). When considering only positive correlations, we found a decrease in performance of the multivariate analysis for rsFC and rsFCNS .Finally, the multivariate analysis using motion information could not significantly infer GA at birth , of 88 infants with gestational age (GA) at birth between 25 and 40 weeks. Note that, since we focused on regression analyses, we mainly treated GA at birth as a continuous variable and we included infants born at term by convention  to increase the numerosity of the sample and the variability of GA at birth. The aim of characterizing the effect of prematurity extent on the brain of newborns thus implies investigating the association of MRI metrics with GA at birth rather than comparing premature infants and infants born at term. To evaluate this association, we exploited the variance of GA at birth in the population under study.Multivariate analyses better captured the effect of prematurity compared with univariate analyses, albeit the two approaches were generally concordant. In accordance with previous studies, the degree of prematurity was associated with bidirectional alterations of functional connectivity and regional volume. Here, we further demonstrated an association between prematurity and the pattern of fALFF, which is a proxy for regional activity. As expected, relevant volumetric effects were identified in specific regions, such as subcortical structures, and their spatial distribution was similar to that of regional activity. This relative spatial specificity contrasted with the highly diffuse effects observed in functional connectivity, supporting the idea that local structural alterations are associated with a widespread effect on the pattern of connectivity.4.1The multivariate analyses showed that rsFC was the functional metric most sensitive to the effect of prematurity Figure  and 5. CConvergent evidence about the long‐lasting effects of prematurity on resting‐state , which has been previously thought to reflect compensatory effects taking place in later phases of brain development . This result extends the findings of a recent study Shang  that repOverall, we believe that the present findings support the view that premature birth manifests as a complex interaction of processes taking place within and between tissue compartments and brain regions Volpe,  and goin4.1.1Consistent with previous work  cannot be straightforwardly interpreted as in the case of univariate analyses, making it difficult to make inferences on the direction of the identified relationships (Carvalho, Pereira, & Cardoso, 4.1.3A limitation of the present study was the use of a short BOLD acquisition time, driven by the limited time available for conducting a relatively nonclinical evaluation in a clinical environment. To maximize the efficacy of the standard clinical assessment, newborns were also mildly sedated using Midazolam, which might have altered brain activity and hemodynamics. Future studies should therefore replicate the present findings using a longer acquisition time and alternative or no sedation approaches. However, longer acquisition times are not expected to modify, but only to expand, our positive findings. Moreover, the newborns in our study were sedated with a Midazolam dosage proportional to their weight. Furthermore, the study did not investigate average functional indices, which are influenced by sedation, but focused on the cross‐sectional differences among newborns as a function of GA at birth. It is therefore unlikely that the observed differences between newborns with varying GA at birth merely reflect a confounding effect of sedation, since this possibility would require that the effect of Midazolam per unit‐weight, when administered at the same PMA, changes as a function of GA at birth, an effect that has not been described in the literature. Even in the presence of residual subject‐specific effects, the disadvantage of small alteration in brain hemodynamics should be over‐compensated by the large reduction in motion artifacts. Another limitation of the present retrospective study was the reduced number of clinical information available for all the infants. Although we explicitly removed from the study infants with evident alterations at standard radiological assessment, and we found no relationship between the main clinical variable that was available for all the newborns, the APGAR score soon after birth (Finster, Wood, & Raja, Research about the effect of prematurity on brain development has the ultimate goal of identifying infants at higher risk of a negative outcome (Rogers et al., 5The present study demonstrated that prematurity is associated with a complex pattern of bidirectional alterations of MRI‐derived BOLD functional connectivity and regional brain volume, and, to a lesser extent, with modification of fALFF. The analysis of the spatial distribution of the effects indicated that structural alterations, which tend to localize to subcortical structures, can have a widespread effect on functional connectivity between cortical structures. The higher sensitivity of multivariate approaches in identifying the complex effects of GA at birth on multiple MRI metrics suggests their use in future studies for the prediction of neurodevelopmental outcome based on the observed neuroimaging alterations.The authors declare no competing financial and non‐financial interests.AppendixS1. Supporting Information.Click here for additional data file.


Simultaneous presentation of omphalocele, patent urachus, and umbilical cyst is very rare. There is wide range of differential diagnosis for umbilical cyst. Accurate assessment of umbilical cysts is important to evaluate other abnormalities. Simultaneous presentation of omphalocele, patent urachus, and umbilical cyst is very rare. There is wide range of differential diagnosis for umbilical cyst. Accurate assessment of umbilical cysts is important to evaluate other abnormalities. It is important to know the wide variety of clinical presentation for early detection of associated anomalies and appropriate surgical approach.A term female neonate, born by Cesarean section, presented with a 10 × 15 cm cystic mass arising from the umbilicus. The mass was translucent and was filled with yellow‐colored fluid. Another 4 × 5 cm mass was visible inside of the large cyst.The inner mass was determined to be an omphalocele. The baby's intestine protruded through a defect in the abdominal wall near the base of umbilical cord and was covered by a nearly transparent sac. Part of the umbilical cord was along the omphalocele and was located inside the large cyst Figure . AntenatOmphalocele concomitant with umbilical cord cysts has infrequently been reported.None declared.RF: wrote and critically reviewed the manuscript and provided the images with description. SAM: was the pediatric surgeon on the case and made final edits.This report for a clinical image was conducted in accordance with the Declaration of Helsinki. Written consent was obtained from the patient's parents.


In this work, we investigate the role of an external electric field in modulating the spectrum and electronic structure behavior of twisted bilayer graphene (TBG) and its physical mechanisms. Through theoretical studies, it is found that the external electric field can drive the relative positions of the conduction band and valence band to some extent. The difference of electric field strength and direction can reduce the original conduction band, and through the Fermi energy level, the band is significantly influenced by the tunable electric field and also increases the density of states of the valence band passing through the Fermi level. Under these two effects, the valence and conduction bands can alternately fold, causing drastic changes in spectrum behavior. In turn, the plasmon spectrum of TBG varies from semiconductor to metal. The dielectric function of TBG can exhibit plasmon resonance in a certain range of infrared. The “magic angle” graphene is similar to the structure of a heterostructure. Bilayer heterostructures have received much attention in recent years, and transition metal element heterostructures exhibit fascinating physical properties ,2. SimilIn this work, we use QuantumATK-2019 program package   to optimWe have theoretically investigated the optical properties of TBG under the modulation of an external electric field, with the lower layer rotated by 21.67° with respect to the upper layer a. We choBy modulating the external electric field, the energy band structure of the TBG exhibits regular changes, and we further investigated the effect of the external electric field on the optical properties see . The optUsually, the optical properties of graphene regulated by an external electric field need to be applied in optical communication devices, and the dielectric function is a crucial element in the simulation process of the devices, so we calculated the dielectric function of TBG under external electric field induction . As can T is the temperature; x is the value of the external electric field; and y is the value of the dielectric function at 1550 nm.The mathematical laws of TBG optical properties modulated by an external electric field are of great importance for the design of modulators, waveguides, and other integrated optical circuit devices. Therefore, we use the law of quantum distribution to fit the relationship between the external electric field and the optical parameters. In fact, we have considered the effect of the Fermi distribution of temperature in the fitting process, and the fitted parameters have physical significance at this time. The fit equation of four curves using the Levenberg–Marquardt algorithm  is shownThe fit coefficients and mean squared deviations (R-square) are shown in In this work, we used the first-principles method to conduct theoretical calculations on the electronic structure and optical properties of the corner double-layer graphene (TBG) in the mid-infrared region under the control of the external electric field. First, it is found that the external electric field has the effect of reducing and increasing the conduction band and valence band of TBG, respectively. As the electric field strength increases, the energy band near the Fermi level can be adjusted in a nearly linear manner. Secondly, the external electric field can control the optical behavior of TBG by adjusting the energy band. The dielectric function near several special positions  in the mid-infrared region is very sensitive to the regulation of the external electric field. In addition, the dielectric function near 1550 nm exhibits certain plasmon properties, which will help the design of new optical communication modulators and optical devices. We complement the scientific gap here with a fit of the parameters. In addition, the near-infrared plasmons controlled by the electric field can be used to enhance the corresponding near-infrared fluorescence and long-wavelength excited Raman spectra.


The effect of short birth interval on socio-economic, negative maternal and child health outcomes remains common in developing countries. This study aimed to assess determinants of short birth interval among reproductive age women, who gave birth in health institution for last six-month in South Gondar, Ethiopia 2019.P-value < 0.05 were used to determine the statistical association.Community-based unmatched case control study design was conducted from February 1 to March 30, 2019. Sample size of 150 was included by simple random sampling technique. The data was collected by semi-structured and pre-tested face to face interviewer-administered questionnaire from selected respondent. The collected data was entered with Epi-Data version 3.1 and analyzed by using SPSS version 23 software. Bivariate and multivariable analyses were used to examine the association. Odds ratio, 95% CI and The mean age of the respondents was 32.42 (SD ± 5.14) and 35.12 (SD ± 5.86) for cases and controls, respectively. Mothers not used contraceptives ), participants who had ≤2 alive children ), mothers who breast fed less than 24 months ), husband decision on contraceptives utilization ) and mothers who did not have history of antenatal care follow up ) were associated with short birth interval.The optimum birth spacing plays a vital role in decreasing fertility and the morbidity and mortality of mothers and children. Thus, providing health information on the benefit of breast feeding, follow-up of antenatal care during pregnancy, use of contraceptives after delivery and encouraging mothers to make decisions about their own health and use of contraceptives to optimize birth spacing for rural communities. Short birth interval is defined as an interval between two consecutive births less than 33 months . After a live birth, the recommended interval before attempting the next pregnancy is at least 33 months in order to reduce the risk of adverse maternal, perinatal and infant outcomes . InstituMore than 200 million women in developing countries want to either space or limit pregnancies and still lack access to options for family planning . DemograStudies in Tanzania showed that short birth interval women will not have sufficient time to recover in terms of socio-economic, cultural, psychological and physical body preparedness for the subsequent pregnancy and failure of vaginal birth after caesarian section . There wAccording to the study conducted in Manipur, Pakistan, Nigeria and Mekele duration of breast-feeding was found to be an independent predictor of birth intervals. It showed that women who breast fed their child for longer than 24 months were more likely to have longer birth intervals –17. As oEven though, institutional delivery service utilization is one of the key and proven interventions to reduce maternal and child morbidity and mortality, short birth interval remains a major challenge in developing countries including Ethiopia particularly rural community . And shoCommunity-based unmatched case control study design was employed from February 1 to March 30, 2019 in rural Farta woreda, South Gondar, Ethiopia. Farta woreda is one of the 15 woredas in South Gondar Zone, located in Amhara National Regional State, Ethiopia. Farta woreda is located 590 km North West from the capital city of Ethiopia, Addis Ababa. The woreda is subdivided in to 32 rural and 1 urban kebeles. In Farta woreda there are 10 health centres, 56 health posts, and 4 privet health clinics. Based on the 2015 demographic survey projection a total of 276,144 populations in the woreda, among these 139,923 are males and 136,221 are females. Women who have less than one-year child is estimated to be 3173.Community-based unmatched case control study design was employed.All reproductive age women residing in rural Farta Woreda who experienced at least two consecutive births and the last delivery occurred in the institution and within the past six months prior to the data collection.All reproductive age women residing in selected kebeles in rural Farta Woreda who experienced at least two consecutive deliveries and the last delivery occurred in the institution and within the past six months prior to the data collection.Reproductive age women who have history of short birth intervals between the latest two consecutive births.Reproductive age women who have history of optimal birth intervals between the latest two consecutive births.All women who gave alive birth within the last six months and have at least two consecutive births with birth interval of 33 and 59 months between the latest two successive live births and the last delivery was in health institution birth.All women who gave birth within the last six months and have at least two consecutive alive births with birth interval of less than 33 months between the latest two successive alive births and had history of last institutional birth.Mothers who had history of abortion between the last two consecutive births and women who live less than 6 months in the study area.1:2 allocation ratio of cases to controls was assumed. An additional non response rate of 10%. Based on the assumptions, the final sample size was determined to be 150 (50 cases and 100 controls).The sample size was determined by using double population proportion formula for unmatched case control study using Open EPI-Info version 7 software by taking of contraceptive utilization from previous study was chosen as an independent variable, since it gives a maximum sample size. The proportion of mothers who utilize contraceptive among controls (controls exposed) 33.25% and not utilize among cases (cases exposed) were considered to be 60.0% . AccordiTen rural kebeles were selected by simple random sampling methods to get the representative sample size. Then, sampling frame was prepared from health extension workers registration book having household identification number. Using respective household identification number, frames of households containing study subjects defined as cases and controls was prepared for each selected kebeles. Then, proportional allocation technique was employed to determine the study participants from each kebele both for cases and controls.Finally, reproductive age women who had at least two consecutive births and whose last delivery been within the past six months prior to the study was selected using simple random sampling technique from the existing sampling frame by lottery method. Participant who were not present at the time of data collection; three revisits were made to interview the woman. In the case of more than one eligible participant in the household, lottery method was used to select only one.Short birth interval practice.Age, occupational status of the mother, marital status of the mother, age at first marriage, ethnicity, educational status of the mother, religion of the mother, husband’s educational status, husband’s occupational status,Age at first pregnancy, gravidity, parity, number of living children, sex of the preceding child, delivery place of the preceding child, survival status of the preceding child, pregnancy plan, antenatal care follows up during previous pregnancy, decision-making power about family planning, maternal and paternal attitude towards contraceptive utilization, breast-feeding practice, type of contraceptive and contraceptive utilization.Short birth interval: when the duration between two consecutive births is less than 33 months.Optimum birth interval: when the duration between two successive births is 33 to 59 months.Long birth interval: when the duration between two successive births is greater than 59 months.Birth to birth interval = birth-to-pregnancy interval (24 months) plus nine months (24 + 9 = 33 months) [ months) .The data were collected by using interviewer-administered, pretested and semi-structured questionnaires after reviewing previous literatures. The questionnaire was first developed in English and translated to local language (Amharic) then back to English by language experts to keep its consistency. Five health extension workers who were familiar with the local language and custom were recruited as data collectors. Two-degree midwives were assigned as supervisor or for the data collectors and overall supervision also made by the investigators. Training was given for data collectors and supervisors for two days on data collection procedures, interview techniques, and confidentiality of the information obtained from the respondents.Data quality was ensured during collection, entry and analysis. Before conducting the main study, pretest was carried out on 5% of the sample size outside of the selected kebeles and necessary modification has been made. The principal investigator and supervisor conducted a day-to-day on-site supervision during the whole period of data collection. At the end of each day, the questionnaires were reviewed and checked for completeness and accuracy by the supervisor and investigator and corrective discussion was undertaken with all the research team members.p-values ≤0.2 on bivariate analysis were selected as candidates for multivariable analysis and then the independent effect of predictors on short birth interval was determined. Odds Ratio and 95% CI was used to measure the statistical association. P-values less than 0.05 were used to determine the statistical significance of the tests. Finally, the results were presented in texts and tables.After coding, the data was entered using Epi-data version 3.1 and then exported to SPSS version 23 software for analysis. Bivariate analysis was executed to examine crude association of predictors with short birth intervals. Finally, variables having After approval, ethical clearance was obtained from Institutional Review Board (IRB) of Medicine and Health sciences, Bahir Dar University. Permission letter was obtained from Farta woreda health office before starting data collection. At the beginning of the data collection, written informed consent was obtained from each respondent after thorough explanation of the purpose and the procedures of the study. Respondents were also informed that all the data obtained from them were kept confidential and anonymous. To ensure confidentiality, names of respondents were replaced by code numbers.This study included a total of 150 child bearing age women who had at least two consecutive births with a response rate of 100%. The mean age of the respondents was 32.42 (SD ± 5.14) and 35.12 (SD ± 5.86) for cases and controls, respectively. About 92.0% of the cases and 97.0% of the controls were married. With respect to religion 96.0% cases. Eighty-four percent of the cases and 85.0% of the controls were farmers  of the cases and 64.0% of the controls breast fed 13–23 months. Sixty eight percent of the cases and 88 % of the controls utilized modern contraceptive method after the delivery of the preceding child before the last child. Thirty percent of cases and 43.0% of controls had no ANC visits during their last pregnancy (Table Sixteen (32.0%) of cases and 12 (12.0%) controls were not use any modern contraceptive at the time of interview. Participants list various reasons for currently not utilizing contraceptives. The reasons for not currently using contraceptives among cases were fear of change in breast milk content as the result of contraceptives, feeling of not exposed to the risk of pregnancy due to breast feeding, religion reason, due to side effect and partner refusal to use contraceptives. Among controls the reason of not utilization contraceptives were, they used amenorrhea and calendar methods.p-values of 0.2 or less were included in the multi-variable logistic regression. As can be depicted from multivariable backward stepwise logistic regression modern contraceptive utilization, number of alive children, breast fed, decision power of contraceptives utilization and mothers who have no antenatal care follow up in preceding pregnancy were found to be significantly associated with short birth interval.First bi-variable logistic regression was conducted among variables with The odds of having short birth interval was higher among mothers who did not use modern contraceptive method before getting pregnant for the last child ) than those who had history of using modern contraceptives. Participants who had ≤2 alive children were strongly significantly associated with short birth interval ).Husband decision of maternal contraceptive utilization was significantly associated with short birth interval as compare to maternal decision ). Mothers who breast fed for the preceding child for less than 24 months were 3 times more likely to have short inter birth interval than their counter parts of mothers who breast fed for 24 months or more ). The odds of having short birth interval was higher for mothers who did not have history of antenatal care follow up in preceding pregnancy than those who had ) (Table This study was aimed to identify factors influencing short inter birth interval among child bearing age mothers who had at least two live births with their last child born within the six months in rural Farta district south Gondar Ethiopia. Short inter birth interval is critical in sub Saharan African countries including Ethiopia, where perinatal mortality and fertility remains still high. However, birth spacing is affected by different factors such as modern contraceptive utilization, number of alive children, breast fed, decision of contraceptives utilization and mothers who have no antenatal care follow up were found to be significantly associated with short birth interval.Contraceptive utilization before gating last pregnancy was found to be a predictor of short birth interval. The finding of this study indicated that mothers who not utilized modern contraceptive method before they got pregnant for her last child were more likely to experience short birth interval than mothers who used contraceptive methods. In line with evidences from studies done in rural pastoral communities of southern Ethiopia, Mekele, Lemo district and Arbaminch district, Ethiopia , 18, 21 Mothers who had less than or equal to two number of alive children were significantly associated with short birth interval. This might be due to women want many numbers of children and number of children are considered as asset especially in rural resident parents.Mothers who breast fed the preceding child for less than 24 months was more likely to have short inter birth interval than their counter parts of mothers who breast fed for 24 months and above. This study finding was similar with evidences from southern Ethiopia, Manipur, Nigeria, Mekele and Arbaminch district –17, 21. Husband who had decision power on maternal contraceptive utilization was another determinant factor of birth interval as compared to maternal her own decision on contraceptive utilization. This was supported by study done in Nepal and rural area of western Ethiopia , 24, resThe likelihood of having short birth interval was 3 times higher for mothers who did not attend antenatal care follow-up during the preceding pregnancy as compared to those who attended it. This might be due to lack of information about family planning counseling and health education during antenatal care follow up and lack of health facility may deter women adhering to optimal birth spacing.Memory bias might be introduced and this study focus on Quantitative approach.Which could not address the “why” questions in detail.Optimal birth interval has significant role in reducing fertility and maternal and child morbidity and mortality. Variables affecting birth interval were modifiable factors. Thus, creating awareness the effect of short birth interval for maternal and children health and impact of high fertility on country, health information about benefit of breast feeding, antenatal care follows up during pregnancy, contraceptive utilization after delivery and empower decision making ability of mothers on their own health and contraceptive utilization to optimize birth spacing for rural communities.