Were the Child Tax Credit (CTC) advance payments that were disbursed in July through December 2021 associated with low birth weight (LBW)?In this cross-sectional study of more than 28 million births to parous people, the odds of LBW increased by a significant 4.2% among births exposed to the CTC .These findings suggest that CTC advance payments did not translate to reductions in LBW, and additional research is needed to evaluate possible explanations for the associated increase in LBW. This cross-sectional study assesses the association of the 2021 Child Tax Credit advance payments to parous people during pregnancy with low birth weight. Infants and pregnant people in the US fare worse on almost all health measures compared with those in peer nations. Families in the US are more likely to live in poverty and have a less generous social safety net, which has generated debate over the contribution of economic conditions to this disparity.To assess the association between temporary increases in income during pregnancy through the 2021 expanded Child Tax Credit (CTC) and birth outcomes.This cross-sectional study applied a comparison-population, interrupted time series design to data from US birth certificates  to test whether the log odds of low birth weight (LBW) among monthly cohorts of births exposed to the CTC would coincide with a decreased incidence of LBW. All singleton live births to US residents aged 15 to 49 years with available data were included.Monthly birth cohorts exposed to the CTC were defined as those born to parous people during the CTC advance payment period from July through December 2021.The main outcome was the natural logarithm of the odds of LBW (<2500 g) among monthly birth cohorts.Among included births (n = 28 866 466), 61.2% were to parous people, the majority were to people aged 20 to 39 years (91.7%), and 6.5% were born LBW. The odds of LBW increased above expected values in 5 of the 6 months of the CTC payments . The outlier-adjusted odds of LBW increased, on average, by 4.2%  among the monthly birth cohorts exposed to the CTC.This study found that the odds of LBW among birth cohorts exposed to the CTC increased above expected values in 5 of the 6 months of the CTC advance payments. Additional research is needed to evaluate rival explanations for this increase in LBW among births exposed to the CTC payments. These programs differ in terms of eligibility requirements and amount and frequency of payments, but they are designed to support increased consumption and asset building.25 The ARPA increased CTC eligibility to children up to age 17 years and raised the maximum credit from $2000 to $3600 per child younger than 6 years and $3000 per child aged 6 to 17 years. Most important for our test, ARPA also changed the format of CTC payments such that instead of waiting until families had filed 2021 taxes, families who had filed taxes in 2020 or who signed up through the Internal Revenue Service’s nonfiler tool received CTC advance payments in the form of a check  each month between July 1 and December 31, 2021. The far-reaching expansion of the CTC policy affected American families with 1 or more children and incomes up to $169 000 for those married and filing jointly, with smaller payments at higher income levels.26 More than 55% of American adults with children reported receiving CTC advance payments. These payments reportedly reduced the number of children living in poverty by 34%27 and reduced household food insufficiency by 26%.28In response to the adverse economic effects of the COVID-19 pandemic, the American Rescue Plan Act (ARPA) expanded an important income transfer program, the Child Tax Credit (CTC).30 we hypothesized that the documented improvement in population nutrition associated with CTC payments28 could have increased fetal growth among those eligible for the CTC. We therefore assessed whether the 2021 CTC expansion coincided with a reduced incidence of LBW among monthly birth cohorts between July and December 2021 to people eligible for the CTC.The timing and nature of the CTC expansion enable assessment of the association between temporary increases in income during pregnancy and birth outcomes. Pregnant people who already had at least 1 dependent child began receiving income transfers in July 2021, whereas those who delivered infants prior to July 2021, as well as those without a dependent child during their pregnancy, did not receive such transfers during pregnancy and, therefore, serve as comparison groups. Because changes in maternal nutrition can affect fetal growth,31 We included singleton births to US residents aged 15 to 49 years (n = 29 535 096). We excluded records missing length of gestation or birth weight and records with implausible combinations of birth weight and gestational age32 (n = 375 469), records from the unrevised (1989) version of the US birth certificate (n = 200 895), and records missing data on previous live birth (n = 92 266) for a final sample size of 28 866 466. We obtained self-reported data on maternal race and ethnicity from the birth certificate in order to describe the analytic population. This study received exempt institutional review board approval from Michigan State University with informed consent waived because the data are publicly available and deidentified. This report follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cross-sectional studies.In this cross-sectional study, we used deidentified data from the National Center for Health Statistics Vital Statistics birth certificate records from January 1, 2014, through December 31, 2021 (most recent available data), which included all live births in the US (N = 30 656 644).We specified our dependent variable as the natural logarithm of the odds of LBW (<2500 g) among 96 monthly birth cohorts to parous people from January 2014 through December 2021. Available data allowed us to observe births exposed to the CTC payments during the second and third trimester of gestation . Our hypothesis assumed that the documented improvement in population nutrition associated with CTC transfers increased fetal growth among pregnant people eligible for the CTC. Low birth weight, however, reflects both fetal growth and length of gestation. We therefore focused our test on monthly birth cohort–level fetal growth by controlling for the odds of preterm birth in the same cohort.Parents with a dependent child are eligible for the CTC. We therefore defined the exposed group as births to people with a previous live birth (as indicated on the birth certificate) since people with a previous live birth  are more likely to have a dependent child compared with people without a previous live birth . As a comparison group, we used births to nulliparous pregnant people, because they are less likely to qualify for the CTC.We used a comparison-population, interrupted time series design (an ecologic study design) to test the hypothesis that the log odds of LBW among monthly cohorts born to parous people after the CTC payment  would differ from their expected values. We derived expected values from preterm births among parous people during CTC payments, LBW among births to nulliparous people (the comparison group) during CTC payments, and autocorrelation in LBW among births to parous people prior to CTC payments. We further adjusted for shocks to  LBW that occurred prior to the CTC payments, such as those that could have arisen from the COVID-19 pandemic. We implemented this design using the following steps , we regressed our dependent variable on the log odds of LBW to nulliparous people and on the log odds of a preterm birth (<37 weeks’ gestation) among parous people.33 detect secular trends, cycles , and the tendency to remain elevated or depressed or to oscillate after high or low values. Any autocorrelation detected in this step logically appears only among low-weight births to parous people because the step 1 regression controls for autocorrelation shared with low-weight births to nulliparous people. We adjusted for autocorrelation because perinatal outcomes, when measured in aggregate within monthly cohorts, show well-documented seasonality, secular trends, and other patterns,34 and births to parous people may exhibit autocorrelation different from that in births to nulliparous people.We used Box-Jenkins methods to identify autocorrelation in the residuals of the regression estimated in step 1. These methods, widely used in engineering and in the natural as well as social and health sciences,For 90 cohorts born before the first CTC payment, we estimated a Box-Jenkins transfer function formed by adding to the regression model estimated in step 1 any parameters needed to fit the autocorrelation identified in step 2. The residuals of the transfer function  gauge the degree to which cohorts differed from their statistically expected value based on the time series model. With coefficients fixed to those estimated in step 3, we applied the transfer function to all 96 monthly birth cohorts, including those exposed to the CTC and born in July through December 2021. If prepayment of the CTC did not change the incidence of LBW to parous people, the residuals of the estimation would fall within the 95% detection interval estimated in step 3. We graphed the residuals as well as the 95% detection interval estimated in step 3. We then inferred that among the 6 exposed monthly birth cohorts, those, if any, with residuals outside the detection intervals yielded an unexpectedly high or low incidence of LBW.We estimated the association of the CTC payment with the odds of LBW by adding a binary variable scored 1 for August through December 2021 and 0 otherwise to the step 4 transfer function and estimating the coefficients for all 96 test months.35 to detect and control any unexpectedly low values of low-weight births immediately preceding CTC payments.We applied outlier management methodsP < .05 was considered significant.The data management was performed using SAS, version 9.4 statistical software (SAS Institute Inc), and the time series analyses were performed using SCA Statistical System, version 5.2 (Scientific Computing Associates). A 2-sided Parous people contributed 61.2% of 28 866 466 included births during the study period . Most biThe results of steps 1 through 3 of our test, in which we identified and estimated a Box-Jenkins transfer function for the log odds of LBW among the 90 pre-CTC monthly birth cohorts, are shown in The results of step 4, in which we applied the step 3 transfer function to all 96 cohorts, appear as a line in The outlier-adjusted regression  yielded a coefficient for the CTC binary variable of 0.042 . This estimate implies that the odds of LBW increased, on average, by 4.2%  among the cohorts born to parous people in the last 5 months of 2021. Application of the observed residual values of the odds of LBW for the last 5 months of 2021 to births to parous people in these months yielded an estimated 2295 excess LBW infants statistically associated with the CTC.23 Few previous studies, however, accounted for time-dependent autocorrelation in the outcome in the test group , identified a clear comparison group, or targeted the exact timing of receipt of income transfers, as we have done in this study. Moreover, other income transfer programs differ from the CTC in terms of eligibility, timing, and enrollment, and findings in Canada may differ due to the country’s more generous social safety net. Our findings are consistent with previous work showing an increased risk of very LBW in the months following the Earned Income Tax Credit (EITC) in California.19 The EITC shares several similarities with the structure of the 2021 CTC in its acute payout structure and focus on parous persons, although income requirements to receive the EITC are lower, so CTC recipients would have, on average, higher income than recipients of the EITC.In this cross-sectional study, we found, contrary to our hypothesis, that the odds of LBW increased above expected values in 5 of the 6 monthly birth cohorts during the CTC advance payment distribution period among births exposed to the payment . These findings differ from previous studies in the US and Canada that showed positive associations of income transfers with birth weight and reductions in LBW.27 and food insufficiency,28 our findings suggest that these benefits did not translate into a reduced risk of LBW. We provide several post hoc explanations for the findings. First, although the CTC was associated with decreased food insecurity, families may have used the payments to benefit existing children and not the pregnant person.37 Use of the CTC payments to benefit existing children would not, however, suggest the observed increase in LBW but would instead suggest a null result.While the CTC payments have been shown to reduce child poverty38 Intuition suggests that this perturbation could have temporally lowered the rate of LBW if it reflected a transient shift in the composition of the reproducing population. Such a lowering could, in turn, have lowered the expectation of LBW in subsequent cohorts, including those exposed to CTC prepayments. Higher-than-expected LBW in the CTC cohorts could, therefore, arise as an artifact of the earlier pandemic rather than as an outcome of the CTC. However, in step 6 of our test, we controlled for the effect of outliers prior to the CTC payments.Second, demographic research has reported a statistically detectable spike in fertility following the COVID-19 pandemic shutdowns.41 although we are unaware of evidence in pregnant populations. However, if even a small subset of pregnant people or people in their households used the CTC in ways that negatively influenced health  or experienced increased stress due to receipt of the CTC, this could result in the observed increase in LBW at the aggregate level.Third, some literature has suggested that cash transfers are associated with increased risky health behaviors,42 This theory posits that natural selection–conserved mechanisms spontaneously abort smaller fetuses , particularly in suboptimal or threatening environments. The standard for how large a fetus must be to avoid spontaneous abortion presumably varies over time. In more threatening environments, the standard increases, resulting in a greater proportion of the cohort being spontaneously lost but a more robust live birth cohort. In resource-rich environments, the standard drops, enabling a greater proportion of smaller fetuses to survive to live birth. The CTC benefit, therefore, could have decreased the standard, implying that small fetuses that would otherwise have been spontaneously aborted survived to birth but, in doing so, increased the odds of LBW in their monthly birth cohorts. We await the release of individual-level birth and fetal death files in coming years to further assess this and other post hoc explanations and to examine birth outcomes after the expanded CTC payments ended in January 2022.A fourth post hoc explanation arises from the theory of selection in utero.Strengths of the analysis include our ability to adjust for seasonality specific to parous people who are pregnant and to control for any temporal patterns in LBW that occur generally across both parous and nulliparous people. By controlling for odds of preterm birth in the exposed group, we also reduce the potential that unexpected values of LBW are driven by increased preterm birth in the cohort. Furthermore, the acute timing of the CTC minimizes the possibility that selection into pregnancy accounts for the results.43 The individual-level association of the CTC payment with LBW among those who received the credit may differ from the average outcome in the exposed population (parous pregnant people). We also could not ascertain trimester of exposure using gestational age dating, which implies that births in our exposed cohorts may have had varying exposure time to the CTC. We await data on births occurring in 2022 (exposed to the CTC payments in the first trimester) to further explore timing of payment during pregnancy.The study also had several limitations. We lacked data on the cash value of CTC received; thus, our identification strategy is like an intention-to-treat framework used for clinical trials.Any test based on other than random assignment has the inherent limitation that some uncontrolled confounder could spuriously induce results. To evade control in our test, however, a confounder would have to affect LBW only among parous (compared with nulliparous) people, have no effect on preterm birth, exhibit no autocorrelation , and appear coincidentally with CTC prepayments. We know of no confounder that meets these criteria.8 Such work could help to inform ongoing policy considerations, such as a permanent child allowance or universal basic income programs.The findings of this study suggest that the relatively generous, but temporary, advance CTC payments received by more than one-half of US families between July and December 2021 corresponded with an increase in odds of LBW. Our findings suggest that the documented reduction in poverty associated with the CTC did not translate to reduced LBW. The theory of selection in utero would support that the CTC could have reduced the number of infants spontaneously lost prior to birth, resulting in a greater proportion of small infants surviving to live birth. We encourage replication and extension of our work to examine the outcomes of the CTC expansion on parental and child health domains over the life course, which may be complex and varied based on prior examinations of income transfers on health.


We found a significant interaction between PlacPRS and birth asphyxia on nHC in the whole sample , with higher placental PRS for SZ associated with lower nHC in those with birth asphyxia. This relationship was specific to males  and also found with their adult ICV . These findings suggest that placental pathophysiology and birth asphyxia may affect early and late trajectories of brain development, particularly in males with a higher vulnerability to SZ. This knowledge might lead to new strategies of treatment and prevention in SZ.The placenta plays a role in fetal brain development, and pregnancy and birth complications can be signs of placental dysfunction. Birth asphyxia is associated with smaller head size and higher risk of developing schizophrenia (SZ), but whether birth asphyxia and placental genomic risk factors associated with SZ are related and how they might impact brain development is unclear. 433 adult patients with SZ and 870 healthy controls were clinically evaluated and underwent brain magnetic resonance imaging. Pregnancy and birth information were obtained from the Medical Birth Registry of Norway. Polygenic risk scores (PRS) from the latest genome-wide association study in SZ were differentiated into placental PRS (PlacPRS) and non-placental PRS. If the interaction between PRSs and birth asphyxia on case-control status was significant, neonatal head circumference (nHC) and adult intracranial volume (ICV) were further evaluated with these variables using multiple regression. PlacPRS in individuals with a history of birth asphyxia was associated with a higher likelihood of being a patient with SZ ( Obstetric complications (OCs) represent one of the best-replicated environmental risk factors for schizophrenia (SZ) and other psychoses , and birUntil early adolescence, total brain volume (TBV) and intracranial volume (ICV) grow in parallel, after which ICV remains static and TBV starts to decrease . The ICVA higher polygenic risk score (PRS) for SZ has been reported in patients with SZ and a history of OCs compared to patients without OCs , a relatPlacPRS genes  were differentially expressed and specifically upregulated in placentae from male offspring compared to placentae from female offspring . In a foWhile the earlier study showed an association between OCs and PlacPRS depended specifically on serious OCs which likely involved hypoxia, the possible specific role of birth asphyxia in driving the interaction between genomic risk for SZ and OCs has not been specifically analyzed , 21. A fhttps://www.med.uio.no/norment/english/). Since October 2002, adult patients with SZ were recruited consecutively from psychiatric units (outpatient and inpatient) of public hospitals in the Oslo region. The controls were randomly selected from the national population register in the same catchment area as the patients and asked to participate. All participants gave written informed consent. The study is conducted in accordance with the Helsinki Declaration with approval from the Regional Committee for Medical Research Ethics for South-East Norway (REK sør-øst) and the Norwegian Data Protection Authority (Datatilsynet).The study is part of the Thematically Organized Psychosis (TOP) study, which is the main study protocol at the Norwegian Center for Mental Disorders Research  module A-E . The AlcExclusion criteria for both patients and controls were organic brain disorders . Participants were excluded if IQ < 70, unable to give consent or not proficient in a Scandinavian language. All MRI scans were assessed by a neuroradiologist using a graded scheme  ~ PRS + covariates) and to assess the relationship between PRS and OCs or birth asphyxia with case–control status (Dx ~ PRS + OCs + PRS*OCs + covariates or Dx ~ PRS + birth asphyxia + PRS*birth asphyxia + covariates) in separate models. Age, sex, population stratification  and genotyping batch were included as covariates in the model. Similar models were used for PlacPRS, and if significant, NonPlacPRS was also examined. We assessed both the whole sample and European Caucasians in separate analyses, because PRSs are derived from summary statistics of GWASs performed on Caucasians. For these analyses, we report in the main text us study , 21.We used multiple regressions to assess the relationship between PlacPRS1 and birth asphyxia on neonatal head circumference . Age, sex, diagnosis, birthweight, gestational age, first 10 genetic principal components and genotyping batch were included as covariates in the model. nHC values were considered an extreme outlier if they fell outside the third or first quartile, +/− 3 × interquartile range, respectively  and subs3 (see Supplementary Table We used multiple regressions to assess the relationship between PlacPRS1 and birth asphyxia on adult ICV (ICV~ PlacPRS1 + birth asphyxia + PlacPRS1*birth asphyxia + covariates). Age, sex, diagnosis, first 10 genetic principal components and genotyping batch were included as covariates in the model. ICV values were considered an extreme outlier if they fell outside the third or first quartile, +/− 3 × interquartile range, respectively  and subst-statistics and one-tailed p-values associated with our variables of interest , based on the directionality of the findings in the previous study ) and those without . DUDIT scores did not differ between male patients with birth asphyxia (mean [SD]: 4.38 [7.06]) and those without  or female patients with birth asphyxia (2.06 [4.98]) and those without .Demographic information on the sample is presented separately for males and females in Table 2 = 0.44, p = 0.508 and χ2 = 0.53, p = 0.466, respectively) between groups. Significantly more OCs co-occurred in the presence of birth asphyxia  than when birth asphyxia was not present . The incidence of SGA was similar between the groups  compared to females  was positively associated with case–control status , confirming that patients had greater polygenic risk for SZ than controls. These results were similar for PlacPRS1 , and NonPlacPRS1  on case–control status . A significant interaction was observed between PlacPRS1 and birth asphyxia on case–control status , suggesting that birth asphyxia may represent a common factor underlying OCs specifically interacting with the placental component of genomic risk for SZ. We did not find a significant interaction between NonPlacPRS1 and birth asphyxia on case-control status , but not for females , but there were too few male patients with birth asphyxia to estimate the model  in male controls with birth asphyxia, but not in female controls with birth asphyxia  birth asphyxia, which is in line with principal findings from the larger study of Ursini and colleagues . We showCommon genomic variants and environmental risk factors related to SZ are frequent in a population and in part shared with other psychiatric disorders, such as bipolar disorder, major depressive disorder, autism spectrum disorder . It is tHowever, in evolutionary genetics, the Conrad Waddington model posits that adverse environmental events and epigenetic changes diminish the capacity to buffer a normal developmental trajectory, which can lead to the decanalization  of a phenotype and increased variability of a trait in a population , 45. UndThere was evidence of a negative association between PlacPRS and adult ICV still being present in male controls with birth asphyxia, which suggests that placental biology related to SZ risk and birth asphyxia influence brain development longitudinally and can affect a phenotype that is associated with susceptibility to the disorder but not necessarily the transition to it. It is possible that the male patients, who experience birth asphyxia, have a more severe neurodevelopmental course, which would preclude inclusion into the study . BecauseOur results do not clearly indicate the molecular mechanisms through which placental genomic risk and birth asphyxia affect altered neurodevelopmental trajectories and risk for SZ. However, they are consistent with the possibility that placental genes play a role and expand the current view on the main etiopathogenetic hypothesis for SZ , which aA possible limitation of our study is represented by the fact that we analyzed a sample where OCs and birth asphyxia do not show an association with SZ. This is in apparent contrast with studies that have shown a consistent association of many severe OCs and birth asphyxia with risk for psychosis and SZ . This inR2 = 0.037 and 0.029, respectively. However, consistent with previous work [It is important to note that the statistical relationship for the PRS1 and PlacPRS1 in the presence of birth asphyxia is weak, with Nagelkerke ous work , the liaous work , PlacPRSous work , 21 indious work .In comparison to previous PRS and OCs studies in SZ , 22, theAnother limitation of this study is represented by the fact that, although PlacPRSs are genomic predictors derived by placental gene-expression data, we cannot exclude that part of the effect of the PlacPRS is related to a more direct effect in the brain of the PlacPRS genes. However, the absence of a significant interaction of NonPlacPRSs with birth asphyxia is consistent with the possibility that genomic predictors based on placental gene expression may have a more specific role in affecting early trajectories of brain development and risk for SZ in individuals with a history of birth asphyxia. Future work may help to refine the calculation of placental genomic predictors by leveraging findings related to genes whose cis-regulated expression in placenta, and not in brain, is associated with SZ .The significant interaction between birth asphyxia and PlacPRS on case-control status revealed that a higher PlacPRS in the presence of birth asphyxia was associated with a higher likelihood of being a patient. Further, a negative association between PlacPRS and neonatal and adult head size was found in males with history of birth asphyxia. These findings suggest that placental pathophysiology and birth asphyxia play a role in affecting early and late trajectories of brain development, potentially linked with a higher vulnerability to SZ in males. New strategies of treatment and prevention may benefit from understanding how placental genomic risk for SZ and birth asphyxia can contribute to the decanalization of brain development.SUPPLEMENTAL MATERIALSupplementary Figures 1 and 2


This paper is concerned with electric–acoustic/acoustic–electric conversions of thin-wafer piezoelectric transducers polarized in the thickness direction. By introducing two mechanical components with frequency-dependent values, i.e., radiation resistance and radiation mass, into the equivalent circuit of the thin-wafer piezoelectric transducer, we established a frequency-dependent dynamic mechanic-electric equivalent network with four terminals for an arbitrary given frequency, an enhancement from the conventional circuit networks. We derived the analytic expressions of its electric–acoustic and acoustic–electric conversion impulse responses using the four-terminal equivalent circuit to replace the traditional six-terminal equivalent circuit for a thin-wafer transducer with harmonic vibrational motion. For multifrequency electrical/acoustic signals acting on the transducer, we established parallel electric–acoustic/acoustic–electric conversion transmission networks. These two transmission network models have simple structures and clear physical and mathematical descriptions of thin-wafer transducers for electric–acoustic/acoustic–electric conversion when excited by a multifrequency electric/acoustic signal wavelet. The calculated results showed that the transducer’s center frequency shift relates to its mechanical load and vibration state. The method reported in this paper can be applied to conventional-sized and small-sized piezoelectric transducers with universal applicability. Vibration is the source of waves; a wave is a vibration state propagating through a medium. The two are closely connected and are the basis of acoustics. Thus, acoustic measurements are essential for measuring particle vibration states inside a medium.Acoustic measurements are ubiquitous in the industry and in daily life. As an essential component in acoustic measurements, a transducer is fundamental for achieving the mutual conversion of acoustic and electric signals. A wide variety of piezoelectric transducers that are conventionally sized and small-sized are applied in many different fields, and some accompanying acoustic phenomena are investigated. In medical and biomedical fields, scientists distinguish normal and pathological issues to prevent, discover, and treat patients carrying some diseases by analyzing the interaction between human tissues and acoustic signals measured by small-sized transducers ,2. Liu eFor different purposes, either application or scientific exploration, scientists have built physical models of many different transducers with various structures, shapes, polarization modes, etc., to study their physical properties using distinct methods. Wang et al. studied interdigital transducers and provided accurate modeling of the piezoelectric effect of coupled structures ,41,42. ZThe transient response of an object, e.g., a transducer, provides information on its physical property and measurement quality. Theoretical and experimental studies reported by Piquette showed that, under the excitation of a sinusoidal voltage signal, the dynamical state on the surface of a piezoelectric transducer went through a transient transition process from a static state to a steady state sinusoidal vibration ,53. MoonIn studies on isotropic solids, Fa and Zhao et al. predicted that the frequency spectrum corresponding to the temporary progression of dynamical oscillations is closely related to the intrinsic noise of the transmission medium, which is related to the internal structure and physical properties of the medium, and the maximum of this frequency spectrum is determined by the solid medium’s resonant frequency and the property of external acoustic disturbance .With our understanding of the physical mechanism of electric–acoustic (acoustic–electric) conversion, this paper reports a frequency-dependent dynamic electric–mechanical network for a single thin-wafer piezoelectric transducer polarized in the thickness direction by introducing radiation resistance and radiation mass . The acoThis study provides a theoretical basis for applying intrinsic noise to acoustic measurements. Based on the analysis of the frequency response characteristics under the excitation of multifrequency-driving signal wavelet, we discuss the physical mechanism of intrinsic noise generated by the electric–acoustic and acoustic–electric conversions of the transducer. Because any object with mass has inertia, there are transient transition processes for electric–acoustic and acoustic–electric conversions as well as the vibrations of particles inside the media. The signals obtained from acoustic measurements contain three kinds of intrinsic noises. The electric–acoustic (and acoustic–electric) conversion properties are vital to extracting noise generated inside the medium for the accurate inversion of its physical properties and internal structure. Studying the transient characteristics of piezoelectric transducers as a general transducer or as a fluid acoustic sensor is essential. One potential application of the research reported in this paper is that by comparing the difference between the integrated frequency responses of source–medium–receiver and source–receiver processes, the physical properties and internal structure of the medium should be inverted accurately from the measured acoustic signals.Let us consider a thin-wafer piezoelectric transducer in a stationary state with a given radius (S3) in the Z direction on the Z surface is nonzero. Because the thickness of the transducer is much thinner than its radius and the intrinsic vibration frequency in the thickness direction is much higher than that in the radial direction, a simplified electric field applied to the transducer in the thickness direction may be helpful. Such a transducer is in a clipped state, with no time to deform in the radial direction, and only the strain component  as . In that case, we may label the component of electric field strength in the Z-axis (thickness) direction  direction asSuppose the insulation performance of a transducer is ideal . Then, only the Multiplying both sides of Equation (3) by the volume of the transducer , we have several related parameters, namely, radiation resistance (mR) for the particle inside the transducer during its vibration, leading to the corresponding frictional force.Due to the viscosity of the piezoelectric material, there is frictional force resistance  disturbance acting on the transducer when vibrating in coupling liquid isDuring vibrations, the transducer is affected by both external forces and self-generated internal stress. Then, we have a complete equation of motion instead of Equation (4).Meanwhile, from Equations (1) and (2), we haveBy the substitution of Equation (9) into Equation (8), we obtainCombined with actual acoustic sensors, we may set the rear surface (Sur1) of the wafer transducer so that it is tightly cemented to the backing layer , and the front surface side (Sur2) is coated with a skinny layer of insulating material; i.e., the front surface is considered approximately free and radiates acoustic waves outward). Because the thickness of the thin-wafer transducer is much smaller than its radius, the edge effect on the establishment of the machine–electric transmission network model is negligible, and we can apply the compression/tension deformation of a uniform rod to the dynamic state of the transducer, as shown in Z-axis direction in l is the thickness of the transducer during its vibration process, and Z is the position of the micro-volume element inside the transducer.The micro-volume element (or particle) displacement in the thickness direction  into Equation (10), the state equation of the transducer vibrating in the coupling liquid can be obtained.Under harmonic vibrations along the thickness direction with the amplitude, The substitution of Equation (16) into Equation (15) yields the following expression.Mechanical compliance Q=∬A combination of Equations (2) and (14) yieldsThe instantaneous current comes from the first-order derivation of the accumulated charge on each electrode surface concerning time. The substitution of Equations (17) and (19) into Equation (18) yields the instantaneous current.Equation (20) is also known as the mechanical–electric state equation of the transducer, where several parameters are the static capacitance of the transducer , as shown in We must pay attention to substantial differences in the characteristics and the analysis methods between conventional circuits and the mechanical–electric equivalent circuit of the transducer. The values of all components, e.g., resistance and inductance, etc., are independent of frequency in conventional circuits. In contrast, some mechanical elements in the mechanical–electric equivalent electric circuits of the transducer are functions of frequency, e.g., radiation resistance and radiation quality, as shown in s domain, as shown in The mechanical–electric equivalent circuits in the time domain, as shown in From the equivalent mechanical–electric circuit of the source, as shown in s domain, the system function of electric–acoustic conversions is a simple ratio of the surface vibration velocity (v(s)) of the transducer to the driving voltage (U1(s)). And from Equations (21) and (22), we haveSince the initial state of the transducer is at equilibrium, the initial energy storage of the relevant electric and mechanical  components  in the mechanical–electric circuit is zero. Any response would have to be from external excitation, and the processes of electric–acoustic (and acoustic–electric) conversions would define the zero-state response. Therefore, in the Let us define a few parameters to simplify the discussion and mathematical derivation: Its discriminant  The discriminant has a negative value  The discriminant is zero (The electric–acoustic conversion impulse response is(iii) The discriminant has a positive value  is integrable with an existing relation  of the excitation signal exerted on the transducer (electric or acoustic). It displays The piezoelectric physical nature and geometric parameters of the transducers guarantee the system is always in an oscillatory mode in practical applications. From Four sinusoidal driving-voltage signals with an amplitude of 1 V are selected, and their four frequencies are selected as 0.1 The calculated results show that when excited by any sinusoidal driving-voltage signal with a given frequency, the transducer will go through a transient process from a static state to a steady sinusoidal vibration state due to the inertia of the particles with mass inside the transducer. When the frequency of the sinusoidal driving-voltage signal is equal to the load center frequency of the source, the source resonates with the sinusoidal driving-voltage signal, and the amplitude of its surface vibration is the largest. This also means that the amplitude of the acoustic wave signal radiated outward by the source is the largest see e. In thiAs mentioned in the earlier section, the acoustic–electric conversion of the transducer is an inverse process of the electric–acoustic transformation but differs in some characteristics. Below, we will analyze and discuss two cases.To analyze only the acoustic–electric conversion characteristics of the transducer, sinusoidal acoustic signals with an amplitude of 1 V and frequencies of 0.1 The calculated results showed a transient process from a zero state to a steady sinusoidal voltage signal at the receiver’s electric terminals. The temporary duration of the acoustic–electric conversion is longer than the electric–acoustic conversion because the amplitude spectrum’s bandwidth corresponding to the transducer’s acoustic–electric conversion is narrower than the corresponding electric–acoustic conversion.For the integrated response characteristics of the source–receiver, we set both the source and the receiver in an ideal liquid (viscosity and acoustic attenuation coefficients are zeroes) with an acoustic velocity of 1500 m per second, and the distance from the source transducer to the receiver is 0.15 m.When excited by sinusoidal driving-voltage signals with an amplitude of 1 V and various frequencies  signal used to excite a transducer can be a linear composition of sinusoidal components with different amplitudes, frequencies, and initial phases. Because radiation impedance and mass are frequency functions, each frequency component corresponds to a different electric–acoustic (or acoustic–electric) equivalent circuit within a circuit network. The electric–acoustic (and acoustic–electric) conversion can be achieved through a parallel transmission network consisting of many electric–acoustic (and acoustic–electric) conversion circuits, as shown in jth frequency component ; the electric–acoustic impulse response  of a sound wave signal; the acoustic–electricity impulse response  is used for measurement control, which consists of an electric-signal module, a display/storage module, and a slippage/rotation module.We placed the source and receiver in a tank filled with water. The virtual panel on a computer screen gave instructions to place the two transducer electrodes opposite of one another at 15 cm apart. The control panel selects the gate-selection sinusoidal driving-voltage signal with an amplitude of 1 V, a gate width of 3 cycles, and frequencies of 0.3, 1.0, and 1.7 By comparing the red dotted line and solid blue line in The measured signal at the receiver’s electric terminals is from the contributions of the driving-voltage signal, the electric–acoustic conversion of the source, the physical property of the medium (water), and the acoustic–electric conversion of the receiver. At the same time, the calculated signal at the receiver’s electric terminals is from the contributions of the driving-voltage signal, the source’s electric–acoustic conversion, and the receiver’s acoustic–electric conversion. The most prominent peak reflects the source, receiver, or medium’s comprehensive frequency response. Meanwhile, the sub-main peak reflects the frequency property of the driving voltage signal used to excite the source.By introducing two components  into the equivalent electric–mechanical circuit developed by predecessors, this paper established a new frequency-dependent dynamic electric–mechanical network for thin-wafer piezoelectric transducers. Because the newly introduced mechanical components are frequency functions, we extended the electric–mechanical circuit model to a parallel circuit network to treat multiple frequency signal transmissions. For the first time, we derived analytical expressions of electric–acoustic/acoustic–electric impulse responses and their transmission functions under the sinusoidal electric/acoustic signals excitation with any given frequency for thin-wafer piezoelectric transducers polarized in the thickness direction. The driving-voltage signal used to excite the source (in electric–acoustic conversion) is a signal wavelet with many frequency components. The particles inside the source transducer have mass and inertia. The vibration of particles inside the receiver and the electric signal at its electric terminals would still go through a transient process, even for a sinusoidal acoustic signal arriving at the receiver. The measured acoustic signal, i.e., the electric signal at the receiver’s electric terminals, will also not be a single-frequency sinusoidal signal. (a)The effects of the transducer’s geometric parameters on various frequencies related to the transducer’s properties presented in By carrying out analytical derivations, calculations, analyses, and experiment measurements, we conclude with the following remarks:In contrast, the loading center frequency varies slightly with the transducer’s steady-state vibration frequency . With re(b)Concerning the frequency bandwidth, the source’s frequency response bandwidth is greater than the receiver’s bandwidth. Due to the electric–acoustic filtering of the source signal, the frequency bandwidth of the radiated acoustic signal is narrower than the driving-voltage signal. Meanwhile, due to the acoustic–electric filtering of the receiver, the frequency bandwidth of the electric signal at the receiver’s electric terminals, i.e., the measured acoustic signal, is narrower than that of the acoustic signal arriving at the receiver.(c)Extending the single-frequency circuit network  to paral(d)Comparing the integrated frequency response of the source–receiver with that of the source–medium–receiver, we can use the measured acoustic signal wavelet to obtain the medium’s physical properties and internal structure accurately.(e)The center frequency shift of the transducer varies with the property mechanical loading (the medium around the transducer) and that of the driving-voltage signal to excite the transducer. If using free loading as a reference, the transducer exhibits higher sensitivity corresponding to lower frequency radiation resistance and radiation mass.(f)Compared with Fa and Zhao’s previous works on thin spherical shells and cylindrical piezoelectric transducers ,8, the tThe new advancement discussed in this paper on the electric–acoustic conversion of the piezoelectric transducer circuit network should be worth some additional points considering the relevant published work in the literature. Piquette’s research has shown that there is a transient transition process in the electric–acoustic conversion of the piezoelectric transducer under the excitation of a sinusoidal electrical signal. The equivalent circuit given by Piquette missed two mechanical components, i.e., radiation resistance and radiation mass, for which their values are frequency functions. Without radiation resistance and radiation mass, the capacitive and inductive reactance generated by the capacitive and inductive components in the traditional equivalent circuit are frequency functions. Still, the values of the capacitive and inductive elements are independent of frequency. Therefore, that work missed carrying out further analyses on the transient transition process of the electric–acoustic conversion of multifrequency electrical signal (wavelet) excitation transducers ,53. Our Although Fa et al. introduced radiation resistance and radiation mass into the equivalent circuit of radially polarized thin spherical shell piezoelectric transducers ,65 when The method described in this paper differs from those of Mason and KLM for thin-disc piezoelectric transducers with respect to thickness polarization , and thev = 2700(1 + 0.005i). In our new model, we applied all factual physical parameters  of piezoelectric materials for calculations and analyses, which is physically more meaningful.Meanwhile, in the equivalent circuit models of Mason and KLM, some physical parameters of piezoelectric materials are assumed to be numerically complex, as shown in Tables 2 and 3 of reference , which iConsidering the work of Sherrit et al.  on MasonAdditionally, the equivalent circuit of Mason and KLM is a six-terminal mechanic-electric network, i.e., four mechanical and two electrical terminals corresponding to two acoustic ports and one electrical port. Two acoustic ports correspond to the front and back surfaces of the thickness polarization transducer, and one electrical port corresponds to the two electrodes on the transducer’s front and back disk surfaces . The disThe transient transition process of particle vibrations inside the transducer reported in this paper also conceptually differs from the transient characteristics reported by Redwood . RedwoodWe conclude that the updated parallel transmission network reported in this paper with the two new physical factors is more realistic relative to the physical nature of a multifrequency signal wavelet excitation transducer. It is applicable not only to conventional-sized but also to small-sized piezoelectric transducers, and it is universal in the descriptions of transducers.


Background: The microbiota acquired at birth is known to play an intimate role in later life health and disease and has been shown to be affected by the mode of birth. There has been recent interest in microbiota correction by maternal vaginal seeding in Cesarean section-born infants; however, the safety of this practice has been debated. The aim of this study was to assess how other factors, such as timing of sampling, maternal obesity, vaginal Group B Streptococcus colonization (GBS), and antibiotic exposure, affect the maternal and infant microbiota.Methods: Maternal vaginal and saliva samples were collected at three time periods: 35-37 weeks gestation , within 24-36 hours after birth (birth), and at ~6 weeks postpartum. Infant saliva and stool samples were collected at ~6 weeks postpartum. 16S rRNA amplicon sequencing was utilized to assess the taxonomic and inferred functional compositions of the bacterial communities from both mothers and infants.Results: Samples from 36 mothers and 32 infants were obtained. Gestational age, breastfeeding, mode of birth, and gravidity were associated with taxonomic alterations in the infant samples, while obesity, antibiotic use, and GBS status were not. Maternal samples were predominantly affected by time, whereby significant alterations including increased microbial diversity were seen at birth and persisted to 6 weeks postpartum.Conclusion: This study provides information on the relationship between health and delivery factors and changes in vaginal and infant microbiota. These results may better direct clinicians and mothers in optimizing the infant microbiota towards health during infancy and later life. The composition of a newborn’s microbiota is altered by a variety of host genetic and environmental factors, and primary colonization occurs at birth by vertical transmission from the mother. During pregnancy, the vaginal microbiota is important for the health of both mother and fetus, and changes in vaginal microbiota are associated with pregnancy complications such as preterm birth and late miscarriage.The human body harbors abundant microbiota, which varies by anatomical site and influences health and disease, including metabolic, immune, and infectious conditions. A vaginal birth exposes the baby to maternal vaginal and fecal bacteria, while Cesarean section-born infants are enriched in skin-associated bacteria,4. After birth, Cesarean section microbial acquisition in the infant has been associated with an increased prevalence of chronic immune conditions. There has been recent interest in the practice of exposing infants to maternal vaginal fluids immediately following a Cesarean birth, commonly known as vaginal seeding. However, this practice does not consider changes in maternal microbiota, potentially putting infants at an increased risk of infection, and the long-term health consequences of vaginal seeding have yet to be established.The mode of birth has been shown to be a major determinant of infant microbiota composition with potentially extensive later-life health implications-9. Obesity rates have been steadily increasing and affect women of reproductive age, with approximately 45% beginning their pregnancy either overweight or obese. Obesity, regardless of and in the case of pregnancy, affects the composition of the microbiota,10 and is associated with higher rates of antibiotic use. Obesity during pregnancy is also associated with longer labors, higher rates of Cesarean section, chorioamnionitis, and Group B Streptococcus (GBS) colonization,16, which in North America is managed with routine antibiotic administration during labor, all factors that may independently affect the acquisition of a normal microbiome. Furthermore, breastfeeding success rates are lower in women who have delivered by Cesarean section and in women with obesity regardless of mode of delivery,19. Importantly, with few exceptions, most pregnancy-related microbiota studies have focused on normal weight mothers or do not follow the infant microbiota, and thus the impact of other pregnancy factors remains unclear-22.In addition to the mode of birth, factors such as maternal body mass index (BMI), antibiotic use during pregnancy, and early-life antibiotic use in the infant are also believed to affect normal microbiota acquisitionThrough an assessment of taxonomic and inferred functional alterations in the vaginal and salivary microbiota from mothers, as well as salivary and gut microbiota from infants, this study sought to highlight the correlations between pregnancy and delivery factors, such as obesity, GBS status, antibiotic use, and breastfeeding, as they relate to changes in maternal and infant microbiota. This information may better direct clinicians and mothers towards optimizing the infant microbiota for later life health.This study was approved by the Health Sciences Research Ethics Board (HSREB# 105630) and written informed consent was received from all participants. Individuals with singleton pregnancies were recruited from London Health Sciences Centre, Victoria Hospital in London, Ontario, Canada. Individuals who received antibiotics in labor for presumed chorioamnionitis or prior to labor for conditions affecting the immune system  were under the age of 18 years or over the age of 40 years, or had a fetus with suspected congenital anomalies, severe growth restriction or chromosomal disorders were excluded from the study. Data such as maternal age, height, pre-pregnancy weight, and gestational weight gain, as well as infant birth weight and type of feeding were collected.Demographic information, GBS screen results, and pregnancy and birth data were obtained from patient charts. An Upset plot was generated in R (version 4.2.1) with the UpSetR package (version 1.4.0) to display the intersection of study participants based on eight birth factors. Additionally, maternal vaginal and saliva swab samples were collected during three perinatal periods: around 35-37 weeks gestation , within 24-36 hours after birth (birth), and at ~6 weeks postpartum (postpartum). Infant saliva and stool swabs were collected at the postpartum appointment approximately 6-8 weeks after birth. All swabs were stored at -80 °C until downstream processing.. A Biomek® 3000 Laboratory Automation Workstation was utilized for automated PCR reagent set-up. Amplifications of the V4 region of the 16S ribosomal RNA gene were carried out with the primers (5'-3') ACACTCTTTCCCTACACGACGCTCTTCCGATCTNNNNxxxxxxxxxxxxGTGCCAGCMGCCGCGGTAA and (5'-3') CGGTCTCGGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNxxxxxxxxxxxxGGACTACHVGGGTWTCT wherein "xxxxxxxxxxxx" represents a sample-specific nucleotide barcode and the preceding sequence is a portion of the Illumina adapter sequence for library construction. The Biomek® robot transferred 2 μL of the DNA template into a plate containing 10 μL of forward and reverse primers (3.2 pmol/µL). Then 20 μL of Promega GoTaq® Colourless Master Mix  was added to the DNA template and primers. The final plate was firmly sealed with a foil PCR plate cover. This plate was placed in the thermal cycler  where the lid was kept at 105 °C. An initial warm-up temperature of 95 °C was used for 2 min to activate the GoTaq®. Afterwards, the volumes underwent 25 cycles of 95 °C for 1 min, 52 °C for 1 min, and 72 °C for 1 min. After completion, the temperature of the thermal cycler was held at 4 °C and amplicons were then stored at -20 °C.Swabs were cut directly into the wells of the bead plate from a 96-well DNeasy PowerSoil HTP 96 kit  and the protocol was followed as per the manufacturer’s directions, as previously describedDNA sequencing was conducted at the London Regional Genomics Centre at Robarts Research Institute . Amplicons were quantified using PicoGreen  and pooled at equimolar concentrations before cleanup . The final samples were sequenced using the MiSeq by Illumina® platform, with 2 × 260 bp paired-end chemistry with a cluster density of 1100 and 5% PhiX. in R. The SILVA Database (version 138) was utilized in assigning taxonomy to the amplicon sequence variants (SVs). Further filtering was performed such that SVs were removed that did not comprise > 1% of the relative abundance in any sample.After sequencing, the paired reads were demultiplexed using custom scripts, then quality filtered, trimmed, denoised, and merged following the DADA2 pipeline (version 1.26.0). Downstream analysis was performed on both gene families  and functional pathways (BioCyc ID). Gene family and pathway counts were not filtered but were rounded to integers for downstream analyses.Inferencing of microbial metagenomes was performed with PICRUSt2 (version 2.4.1). The zero-adjusted counts underwent centered log ratio (CLR) transformation and a principal components analysis (PCA) was performed. PCA biplots were generated with ggplot2 (version 3.4.2). Sample type comparisons of Aitchison distance (β-diversity) were calculated by PERMANOVA with the adonis2 function from the vegan R package (version 2.6-4). Potential covariates of microbiota composition were determined using the envfit function from the vegan R package with the Aitchison distance PCA as the input object. Differential abundance tests of taxonomy, inferred gene families, and functional pathways were determined using a generalized linear mixed model approach with the MaAsLin2 R package (version 1.12.0). Briefly, CLR-transformed counts were used as the input, and the fixed effects were potential covariate clinical metadata features with an envfit P-value < 0.1. For maternal samples, the longitudinal repeated measures were accounted for by treating the ‘participant’ as a random effect. For all differential abundance analyses, Benjamini-Hochberg adjusted P-values  < 0.1 were considered significant. Co-occurrence network analysis was performed using CoNet software (version 1.1.1), as previously described,33, where only significant  edges were plotted. CoNet networks were visualized in Cytoscape (version 3.8.2), then the final copresence and mutual exclusion network figures were generated with Circos (version 0.69-9). Relative network positivity was calculated as the number of copresence edges divided by the number of mutual exclusion edges. Network property and baby stool microbiota origin figures were generated with GraphPad Prism (version 9.5.1).Alpha diversity (Shannon’s Index) was calculated using custom R scripts. A Kruskall-Wallis test followed by a Dunn’s multiple comparison test  was used to test for alpha diversity differences between sample subgroups. Sparsity in read count data was zero-adjusted with the cmultRepl function from the zCompositions R package (version 1.4.0-1)A total of 36 mothers and 32 infants were recruited for this study. Patient demographic characteristics are summarized in 2 = 0.159, P < 0.001; P < 0.0001). The diversity of baby saliva was significantly lower than the mothers’ . Vaginal diversity was lowest in the prenatal samples and was significantly increased following birth and in the postpartum samples . Following quality filtering with DADA2, the 16S dataset yielded 11,820,704 reads; the average sample read depth was 46,175 . 1341 unique SVs were initially identified, with 271 SVs remaining after filtering out those that did not comprise > 1% of the relative abundance. For the principal component analysis (PCA) of all samples, 30.5% of the total variance was explained by the first two principal components . The samP < 0.1, Supplementary Table 1] were accounted for and sample type subgroups were explored for trends based on clinical features in a multivariate manner [Supplementary Tables 1 and 2]. Perinatal period was the most significant covariate associated with taxonomic and functional changes in the maternal vaginal samples (P < 0.001), though BMI and gravidity were also significant factors. Vaginal samples were dominated by lactobacilli prenatally [Supplementary Table 2], whereas samples from the birth and postpartum periods were significantly altered in 74 SVs and 36 genera when SV counts were aggregated by genus [Supplementary Table 2]. These postpartum alterations included relative enrichment of the genera Dialister, Prevotella, Escherichia, and Streptococcus. BMI was negatively correlated with Gemella and Megasphaera, while primigravida was associated with a relative depletion of Escherichia.Potential covariates . In baby saliva, the covariates of breastfeeding, gestational age and primigravida were adjusted; infants born prior to 37 weeks harbored relatively more SV41: Limosilactobacillus fermentum than those born after 37 weeks , while infants born out of primigravid pregnancies harbored relatively less of the genus Escherichia , SV3: Escherichia , and SV14: Bacteroides  compared to infants of multigravidae.Delivery method and infant sex were determined to be potential covariates of baby stool microbiota. After accounting for these factors, the genus Supplementary Table 3]. Several of these enzymes are involved in lipopolysaccharide (EC.2.4.1.58) or E. coli O-polysaccharide biosynthesis . Infants delivered vaginally were also relatively depleted in 13 functional pathways compared to those delivered by Cesarean section [Supplementary Table 4]. Several of these functional pathways were Pseudomonadota-specific, including 3-phenylpropanoate degradation (PWY0.1277) and sulfoquinovose degradation (PWY.7446).When investigating microbiota function, baby stool was significantly shaped by the delivery method, whereby infants delivered vaginally were relatively depleted in 41 different gene families compared to those delivered by Cesarean section [Supplementary Tables 3 and 4]. For example, breastfed infants had a relatively lower abundance of EC.1.6.3.4, an NADH oxidase enzyme likely originating from Streptococcus mutans (Q = 0.009), and infants from primigravidae had a relatively lower abundance of the functional pathway for biosynthesis of the virulence factor enterobactin (Q = 0.005).Baby salivary microbiota function was significantly shaped by gravidity, gestational age, and breastfeeding [P = 0.007; Lactobacillus iners, Lactobacillus crispatus, Lactobacillus jensenii, and Streptococcus spp.), whereas more rare taxa were not consistently shared.To track the potential source of baby stool taxa, dyad analysis was performed by determining shared SVs between i) baby stool and baby oral microbiota, and ii) baby stool and vaginal microbiota. This analysis was performed on the filtered SV counts table, so all non-zero SV counts in dyad samples were considered shared. On average, baby stool samples contained 54 SVs, of which 54%, 58%, 53%, and 60% were shared with the baby’s saliva, prenatal vaginal, birth vaginal, and postpartum vaginal samples, respectively , as the Aitchison distance between the baby gut microbiota and prenatal vaginal samples was lower than the distance between dyads with Cesarean delivery [Beta diversity (Aitchison distance) between the baby fecal and prenatal vaginal sample pairs was investigated as a marker of vertical transmission and microbiota engraftment. In these comparisons, the shorter the Aitchison distance, the more similar the baby fecal and prenatal vaginal sample microbiota, suggesting increased “engraftment” from the vaginal microbiota into the baby’s gut. This “engraftment” was compared between different birth factors to explore which, if any, influenced the diversity between the sample dyads. Vaginal delivery led to significantly more engraftment  warrant further exploration in larger longitudinal studies to determine the role (if any) they have on microbiota development and overall health later in life.Maternal obesity was significantly associated with variation in only the vaginal microbiota, indicating that it may not be as relevant to the infant microbiota as other birth factors including mode of delivery, primigravity, breastfeeding, and gestational age. Again, it is possible that our limited sample size and heterogeneous maternal population decreased power to detect significant microbiota-related factors, or that infant manifestations of the relevant factors were detectable beyond the postpartum timepoint measured in this study (6-8 weeks after birth)Clostridioides difficile infection has led to the proposal of transplanting alternative materials and anatomical regions, including the vaginal microbiome for bacterial vaginosis and urinary tract infection-60. Similarly, based on the known negative associations with Cesarean section microbial acquisition, interest in microbiota correction by maternal vaginal seeding has increased in recent years,61-63. While this field is still evolving, it is important to characterize the optimally efficacious donor sample; studies diverge in this regard, with some utilizing maternal vaginal material, others suggesting maternal gut material, or even arguing that species-specific restoration is sufficient. While maternal stool was not investigated here, beyond any other birth factor, perinatal period was the most significant driver of vaginal microbiota community structure and function. The baby stool microbiota also shared the fewest microbial taxa with the vaginal sample collected at birth. Thus, if indeed vaginal seeding is to be undertaken, the sample should be collected prior to the onset of labor, after which the microbial community structure and overall function significantly change without recovery by 6 weeks postpartum. The extended displacement of vaginal lactobacilli during and after birth indicates that additional microbial therapeutic support may be advantageous to all perinatal individuals, and not just those with Cesarean births. Maternal probiotic supplementation during pregnancy and postpartum has shown promise in long-lasting health outcomes in both mother and child related to obesity,66, allergy, depression and anxiety, and necrotizing enterocolitis, among other conditions, warranting consideration for incorporation into standard perinatal care.The success of fecal microbiome transplant for microbially-involved and systemic diseases beyond ,70, it is not a replacement for whole shotgun metagenomic sequencing which could be employed in the future to validate the current findings.This study has several limitations. As previously mentioned, the sample size was modest, and the maternal cohort was heterogeneous in BMI, antibiotic exposure, GBS status, age, delivery, and infant feeding method. Although a multivariate approach was undertaken to account for such differences, a future study with a larger sample size could have better precision in detecting and adjusting for potential confounders. Maternal stool was also not investigated here. This study employed 16S rRNA amplicon sequencing of all samples; this technique provides relative compositional, but not absolute abundance information. It also did not provide taxonomic annotation to the species level in all cases, so caution should be taken when comparing these data and taxonomic annotations in future studies. The 16S rRNA amplicon data were used to infer functional metagenomes with PICRUSt2; although this technique demonstrates accuracy in samples of human origin, it is important to concurrently study these features and their interaction and effect on both the maternal and infant microbiota. Whether these differential features manifest in the infant’s later life disease risk requires additional study.Overall, this study provides the first look at how a multitude of birth factors may influence maternal and infant microbiota. The maternal salivary and vaginal microbiota were associated most significantly with temporal factors related to birth, while the infant samples were influenced to a lesser degree by a range of factors including mode of delivery, breastfeeding, and gestational age. As obesity, GBS status, and antibiotic use continue to increase in our population


The World Health Organization (WHO) defines Preterm Birth (PTB) as “a live birth taking place before the expected 37 weeks of gestation”. Annually, approximately 15 million infants are born prematurely, constituting significantly to infant mortality during the initial four weeks of life, responsible for 40% of deaths among children under the age of five. Evidently, preterm deliveries have contributed to 46% of admissions to the neonatal intensive care unit (NICU) at Lira Regional Referral Hospital (LRRH) over the past three years. Paradoxically, while the prevalence of preterm births remains high, there is a lack of documented information regarding the underlying risk factors. Consequently, the primary objective of this study was to assess the potential risk factors associated with preterm birth at LRRH.p < 0.05 to establish statistical significance. Furthermore, assessments for multicollinearity and model fitness were conducted using the Variance Inflation Factor (VIF) and linktest, respectively.An analytical cross-sectional research was undertaken at LRRH, employing a quantitative methodology. The study utilized secondary data obtained from a total of 590 comprehensive maternal medical records, of deliveries that occurred at the facility between April 2020 and July 2021. The collected data underwent analysis using STATA version 17 software. To identify predictors of preterm birth, a Logistic regression model was applied, yielding adjusted odds ratios (AOR) alongside 95% confidence intervals (CI). The significance level was set at p = 0.037, 95%CI: 0.443–0.975); having a baby with low birth weight  and experiencing preeclampsia  were also identified as significant predictors of preterm birth in the study.The prevalence of preterm delivery among mothers who gave birth at LRRH stood at 35.8%. The outcomes of logistic regression analysis revealed that maternal employment status had a statistically significant association with preterm birth  among mothers who gave birth at LRRH when compared to the national average (13.6%). The prevalence of preterm birth among mothers was linked to factors such as employment status, delivery of low birth weight infants, and the presence of preeclampsia. Consequently, the research proposes a set of recommendations. Firstly, the Ministry of Health (MoH) should evaluate the present state of readiness within the healthcare system to effectively handle cases of preterm birth both within medical facilities and the community. Secondly, the Ministry of Gender, Labour, and Social Development should leverage Labor Officers to implement and uphold the regulations stipulated in the Employment Act and Labor Laws.The online version contains supplementary material available at 10.1186/s12884-023-06120-4. Preterm birth (PTB), as defined by the World Health Organization (WHO), refers to “a live birth taking place prior to the completion of 37 weeks of gestation” . AnnuallPreterm birth rates in Sub-Saharan Africa have been investigated, revealing estimates of 10.9% in Gambia and 12% in Tanzania . Within To address the issue of premature births, the Ministry of Health, operating under the Government’s initiative, has established a nationwide framework for pregnancy care and assistance. This includes bolstering emergency medical services and referral systems, enhancing maternal, neonatal, and child health provisions across all tiers of healthcare, expanding access to sexual and reproductive health amenities with a particular emphasis on family planning and age-appropriate information, and elevating the quality of national laboratory and diagnostic services . AdditioThe collection of secondary data involved the retrieval of information from the medical documents  of mothers who gave birth at LRRH during the period from April 2020 to July 2021. A cross-sectional sample of 590 comprehensive records of mothers who gave birth at LRRH was examined.The dependent variable in this study was preterm birth, dichotomized as birth occurring before 37 weeks (preterm birth) and at 37 weeks or later (term birth). Accordingly, a mother who gave birth before 37 weeks was classified as having experienced preterm birth and assigned a code of 1, while a mother who delivered at 37 weeks or beyond was categorized as having undergone term birth and assigned a code of 0.The independent variables included various aspects of family socio-demographics. Age was measured in completed years and subsequently grouped into three categories during the analysis: <18 years, 18–30 years, and 31 years or older. Marital status was stratified into four categories: married, single, divorced, and widow/widower. Education level was divided into four categories: no education, primary education, secondary education, and tertiary education. Employment status was dichotomized as employed or not employed. Location was classified as rural or urban. Other independent variables included Body Mass Index (BMI) measured in kg/m², which was segmented into four categories during analysis: underweight, normal weight, overweight, and obese. Substance use was categorized as active drug user or not an active drug user. Maternal factors were also considered, with mode of delivery categorized as either normal delivery or caesarean section. Antenatal Care (ANC) attendance was categorized as either less than 3 times or 3 times or more. Anemia was divided into two categories: <10 g/dl and ≥ 10 g/dl. History of abortion was classified as either having experienced abortion or never having experienced abortion. The birth weight of the mother’s baby was grouped into “yes”  or “no” . Comorbidities were classified as, whether present or absent. HIV status was categorized as sero-positive or sero-negative. Parity was stratified as having fewer than 4 children or having 4 or more children. Inter-pregnancy interval was segmented as less than 24 months or 24 months or more. Previous preterm birth was dichotomized as “yes” or “no,“ and preeclampsia was similarly classified as present or absent. Furthermore, fetal factors were considered, including the sex of the child, categorized as male, female, or both (in the case of twins of different sexes). Pregnancy outcome was classified as singleton or twins. Congenital abnormalities were recorded as “yes” or “no.“p < 0.05. Factors that demonstrated significance in this analysis were selected for inclusion in the subsequent multivariate analysis. The purpose of the multivariate analysis was to estimate the individual net effects of each independent factor on the dependent variable. Notably, due to the low prevalence of preterm births (ranging from 5 to 18%) as indicated in the literature, which categorizes it as a rare event, the binary complementary log-log model was a potential choice for isolating net effects, as opposed to the logistic and probit models. However, an evaluation of three Link functions  was performed to determine their suitability for fitting the data. Based on the Akaike’s Information Criteria (AIC) and Bayesian Information Criteria (BIC), the logistic model exhibited the lowest AIC and BIC values, rendering it the most plausible model for identifying predictors of preterm birth. Subsequently, two diagnostic tests were executed: a multicollinearity test and a model fitness test employing the Variance Inflation Factor (VIF) and link test, respectively.The data analysis was conducted using STATA version 17.0 software. In the initial univariate analysis, frequencies and percentages were computed to describe the variables considered in the study. At bivariate analysis, associations were examined using the Pearson Chi-square test with a significance level set at This study employed the Research Ethics Committee of Makerere University’s School of Statistics and Planning to obtain approval and oversee the research process, ensuring adherence to both the regulations set forth by the Uganda National Council for Science and Technology (UNCST) and other international guidelines concerning the involvement of human subjects. The study made use of aggregated data sourced from a hospital, for which institutional authorization had been obtained to carry out the research. Informed consent was not pursued, as the data extracted did not contain any elements that could potentially reveal the identities of the patients. Physical copies of the data were securely stored and accessible solely to the research team. Similarly, electronic databases were safeguarded with passwords, with access restricted exclusively to the research team. Lastly, a request for a waiver of consent was submitted to Lira Regional Referral Hospital, an entity established to ensure the protection of study participants.The research employed pre-existing data gathered at the establishment. The occurrence of the Covid-19 pandemic influenced the quantity of mothers who gave birth at the facility during the specified time frame (April 2020 to May 2021). To tackle this issue, the investigation period was prolonged until July 2021. Certain instances of insufficient or absent information, notably within the records, were faced. Nevertheless, this challenge was managed by incorporating information from antenatal cards to supplement the absent data.Table p = 0.027) is notably associated with preterm birth.Table p = 0.037), low birth weight baby , preeclampsia , and previous preterm births .An analysis of maternal characteristics demonstrates significant associations with preterm birth. These include parity  and pregnancy outcome  are also significantly associated with preterm birth.Furthermore, an analysis of fetal characteristics indicates that the sex of the child .The factors that were found to be statistically and significantly associated with preterm birth during the bivariate analysis were further examined in multivariate logistic regression. These factors were; employment, parity, low birth weight baby, preeclampsia, previous preterm births, pregnancy outcomes, and the sex of the child. In Table p < 0.001, 95% CI: 0.099–0.527). Furthermore, mothers without preeclampsia exhibited an approximately 86% reduced odds of experiencing preterm birth when contrasted with mothers who had preeclampsia .Examining maternal factors, the results revealed significant associations between preterm birth and having a baby with low birth weight and experiencing preeclampsia. In this regard, mothers who gave birth to babies weighing 2500 g or more displayed a nearly 77% reduced odds of having a preterm birth, in comparison to those who gave birth to babies weighing less than 2500 g , being 0.657 times less likely to deliver preterm babies compared to those who were employed. This outcome aligns with studies conducted in Indonesia, which identified that working mothers faced a 16.2 times higher risk of delivering late preterm infants (LPI) in comparison to housewives  [p = 0.021) was associated with a 64% reduction in the likelihood of experiencing preterm birth [p = 0.428) and birth weight  at delivery. Nevertheless, it did significantly affect stillbirth rates  [The study anticipated that socio-demographic characteristics, such as age, BMI, marital status, education level, location, employment, and drug use , would not exhibit a significant association with preterm birth among mothers delivered at LRRH. However, the findings revealed that employment emerged as a noteworthy predictor of preterm birth. According to the results, mothers who were unemployed demonstrated a significant difference  ; in Mulap < 0.001, 95% CI: 0.099–0.527). Accordingly, mothers who gave birth to babies with a weight of ≥2500 g were 0.228 times less likely to experience preterm birth than those who gave birth to babies weighing < 2500 g. This finding aligns with studies conducted at Shire Suhul General Hospital in Northern Ethiopia. Those studies discovered that mothers with a history of bearing neonates weighing less than 2500 g, including the most recent birth , were 2.8 times more likely to have preterm deliveries compared to their counterparts [p < 0.001) increased the likelihood of preterm delivery by a factor of 0.085 compared to those without a history of poor birth outcomes [p < 0.001) were nearly 18 times more likely to experience preterm births than their counterparts [p < 0.001) had a 3.78 times higher likelihood of being delivered preterm than babies with birth weights of ≥2500 g [The study hypothesized that antenatal care (ANC) visits, mode of delivery, parity, history of abortion, inter–pregnancy interval, mothers with low birth weight babies, HIV status, comorbidity, anemia, preeclampsia, and previous preterm births are not significantly associated with preterm birth. However, this study found that mothers with low birth weight babies and preeclampsia were statistically significant predictors of preterm birth. The statistical analysis indicated that a mother with a low birth weight baby was a statistically significant predictor of preterm birth . This implies that mothers without preeclampsia were 0.254 times less likely to experience preterm birth than those with preeclampsia. This result is consistent with studies conducted at Mukalla Maternity and Childhood (MCH) Hospital in Yemen, which revealed that mothers with pre-eclampsia  were 4.12 times more likely to deliver preterm babies than those without [p < 0.001) were 16 times more likely to have a preterm birth than mothers without preeclampsia [p < 0.001) than for mothers without the condition [p < 0.001) were 3.4 times more likely to experience preterm delivery than those without preeclampsia [Additionally, preeclampsia was a statistically significant predictor of preterm birth  were three times more likely than those without any birth defects to experience preterm birth [p < 0.05) increased the odds of preterm birth occurrence compared to normal babies [The study also hypothesized that fetal factors  are not associated with preterm birth. However, this study revealed that no fetal factors were associated with preterm birth, which contradicts studies conducted in Public Hospitals of the central zone, Tigray, Ethiopia. These previous studies showed that neonates with congenital/birth defects  and its related determinants within the context of deliveries at LRRH. The prevalence of preterm birth among mothers who gave birth at LRRH was documented at 35.8%. Specifically, the likelihood of preterm delivery was found to be lower among unemployed mothers in comparison to their employed counterparts. Similarly, mothers whose babies had a birth weight of less than 2500 g were observed to have a higher probability of delivering preterm compared to those whose babies had a normal birth weight. Conversely, the presence of preeclampsia was associated with a greater probability of preterm birth, whereas mothers without preeclampsia exhibited a reduced likelihood of delivering preterm babies.Basing on the key findings from the study, the followings recommendations were made:To address the elevated occurrence of preterm birth within the LRRH and Lango sub-region, it is imperative for the Ministry of Health to evaluate the existing state of the healthcare system’s readiness to handle preterm births. This involves devising comprehensive plans and making necessary preparations, particularly in terms of procuring essential equipment. Furthermore, conducting training and mentorship programs aimed at imparting vital managerial and clinical proficiencies is essential. These programs are designed to empower frontline healthcare providers in promptly identifying and effectively managing expecting mothers who face a heightened risk of preterm birth. A crucial aspect of this initiative involves bolstering the referral system, ensuring a seamless pathway for timely and appropriate care. Concurrently, elevating the quality of antenatal care necessitates the implementation of routine antenatal ultrasounds. This step aims to enhance the identification of fetal antenatal conditions, contributing to improved care. Additionally, providing multiple micronutrient supplementation to pregnant mothers at risk of preterm birth emerges as a fundamental strategy to augment the overall quality of antenatal care.Expectant employed mothers within the area must receive safeguarding from the implementation of the Employment Act and Labor Laws by the Ministry of Gender, Labour, and Social Development. This can be achieved by deploying Labor Officers, a measure aimed at addressing the concern of premature childbirth among working mothers.To effectively reduce the occurrence of preterm birth and its associated consequences among mothers with preeclampsia and low birth weight infants in the LRRH and the broader Lango sub-region, it is crucial for healthcare professionals to recognize expectant mothers who are susceptible to delivering prematurely. This should be followed by the implementation of high-quality medical interventions, community-based health education, as well as informative awareness initiatives.The study emphasized the necessity for additional quantitative and qualitative investigation into the factors contributing to preterm birth. The comprehensive information gathered from maternal participants and other relevant sources will enable the identification of unexplored variables, thus influencing the development of treatments and policy strategies.Below is the link to the electronic supplementary material.Supplementary Material 1


Inspired by the rhetorical/relational goal theory, the current inquiry evaluated the role of two teacher relational behaviors, namely care and confirmation, in predicting Chinese EFL learners’ empowerment.To do this, we administered three closed-ended scales to 391 Chinese students who studying English as a foreign language in various educational institutions in China. Students’ attitudes toward the interplay between teacher care, teacher confirmation, and learner empowerment were statistically analyzed using IBM SPSS Amos software.The results uncovered that teacher confirmation and teacher care serve an essential role in improving Chinese EFL learners’ empowerment. This indicates that EFL learners’ empowerment strictly depends on the relational behaviors that teachers employ in instructional-learning contexts.The study outcomes may have some theoretical and practical implications for L2 researchers, language teachers, and teacher trainers. In line with this necessity, some earlier studies e.g.,  has lookOne teacher-related factor that may play some role in increasing or decreasing learner empowerment is teacher care. Teacher care is a positive communication behavior that teachers use to address the psychological, emotional, and academic needs of learners . In the Another teacher-related factor that may make a noticeable change in learner empowerment is teacher confirmation. Teacher confirmation is another instance of positive communication behavior by which teachers inspire their learners and make them feel valued . AccordiIn view of the key role of teacher care and teacher confirmation in promoting learners’ academic engagement, motivation, and well-being, many scholars . The participants were all chosen based on their propensity and perceived capacity to accurately respond to the questionnaire items. A consent letter was administered to them before they engaged in the research process.In the current research, the participants were 391 EFL learners recruited from different educational institutions in China. The participants in this inquiry were chosen based on the convenience sampling strategy. As put by 3.2.3.2.1.Teacher Confirmation Scale (TCS)”  “Takes time to answer students’ questions fully,” and item (25) “Incorporates exercises into lectures when appropriate.” The Cronbach’s alpha reliability of 0.94 was found for this inventory.To measure this positive communication behavior, the “e (TCS)”  was empl3.2.2.Perceived Caring Scale (PCS)”  “Understands how I feel/Does not understand how I feel,” and item (10) “Does not understand how I think/Understand how I think.” The Cronbach’s alpha coefficient of PCS in this inquiry was 0.92.To evaluate English learners’ standpoints concerning their instructors’ caring behaviors, the “e (PCS)”  was admi3.2.3.Learner Empowerment Questionnaire (LEQ)”  “I like to talk about what I’m doing in my class with friends or family,” and item (21) “My success in this class is under my control.” The LEQ’s reliability was estimated to be 0.97 in this research.The “e (LEQ)”  was dist3.3.N = 391) completed the questionnaires and submitted them within 15 days. The respondents’ perceptions of the interplay between the constructs were statistically analyzed through the IBM SPSS Amos software. The IBM SPSS is an easy-to-use software that allows researchers and analysts “to specify, estimate, assess, and present models to show hypothesized relationships among variables”  was run to check the validity of the constructs under investigation . The outcomes of this statistical procedure are presented below .The CFA outcomes disclosed that almost all of the values are higher than 0.5, acknowledging the validity of the variables and their components. With respect to the above values, the initial CFA model was drawn .Next, the goodness of the initial CFA model was assessed and the results are demonstrated in the following table .As represented in the above table, the fit indices, including “CMIN-DF,” “Goodness-of-Fit Index (GFI),” “Comparative Fit Index (CFI),” “Parsimonious Normed Fit Index (PNFI),” “Tucker–Lewis Index (TLI),” and “Root Mean Square Error of Approximation (RMSEA)” are all within specifications . This coThe test results revealed that the proposed CFA model has an acceptable level of discriminant validity (the square root of AVE > inter-construct correlations). Following that, to respond to the first research question, the associations between teacher care, teacher confirmation, and learner empowerment were computed through a set of correlation tests. The results of correlation tests are displayed in the table below .In accordance with the correlation test outcomes, a close and positive relationship exists between teacher care and learner empowerment. The test results also demonstrated that there is a favorable and strong association between teacher confirmation and learner empowerment. As the outcomes of the correlation test revealed, teacher confirmation is also closely related to teacher caring behaviors. Finally, to address the second research question, the dataset was subjected to linear regression analysis. The analysis findings are portrayed in the following figure .According to the above figure, teacher care accounts for about 87 percent of the change in Chinese EFL learners’ empowerment, and teacher confirmation accounts for about 73 percent of the change. This means that these positive communicative behaviors can play a significant role in empowering EFL learners.5.This inquiry was planned to explore the interplay between teacher care, teacher confirmation, and learner empowerment in Chinese EFL classes. The research outcomes first revealed that teacher confirmation and teacher care are tightly connected to learner empowerment. The study findings also demonstrated that teacher confirmation and teacher care can bring significant changes in Chinese EFL learners’ empowerment. This means that positive communication behaviors like care and confirmation make EFL learners feel empowered.The outcome of this inquiry about the close and favorable associations between teacher care, teacher confirmation, and learner empowerment lends support to the main principles of rhetorical/relational goal theory , which eThe findings of the current inquiry are subject to a set of limitations, which necessitate future empirical research on this issue. First and foremost, the current research study was conducted exclusively in China, as a result of which the findings might not be applicable to other EFL countries. Thus, future inquiries need to be performed in other EFL countries across the globe . Second,6.This investigation was carried out with the aim of studying the implications of two positive communication behaviors, namely teacher care and teacher confirmation, for Chinese EFL learners’ empowerment. In fact, the present research sought to unravel the role of teacher care and teacher confirmation in empowering Chinese EFL learners. The results of linear regression analysis disclosed that teacher care and teacher confirmation play a significant role in empowering EFL learners. Put it another way, these teacher communication behaviors direct EFL learners to higher levels of empowerment. The results of this inquiry may have a number of theoretical and practical implications for L2 researchers, teacher educators, and language instructors. As to the theoretical implications, the present research extends the existing literature on the interplay between teacher communication behaviors and learner educational outcomes by highlighting the positive impacts of teacher care and teacher confirmation on English learners’ empowerment. As to the practical implications, the study outcomes may be of great help for language instructors in empowering their learners. In fact, the results of the present investigation expand language instructors’ understanding of the role of positive communication behaviors like care and confirmation in promoting learner empowerment. Likewise, these outcomes may also be insightful for teacher educators. According to the present results, positive communication behaviors have favorable impact on language learners’ empowerment. Thus, teacher educators are expected to teach their teacher students how to use positive communication behaviors in different instructional contexts.The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.The studies involving humans were approved by Academic Ethics Committee of Jiaozuo Normal College and Zhengzhou University. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.ML: Formal analysis, Writing – original draft, Writing – review & editing. ZC: Data curation, Methodology, Visualization, Writing – review & editing.


Epidemics in the Pacific Islands noted flu-like symptoms and complications following human ZIKV infection. However, after a severe outbreak in 2015, Latin American studies reported fetal birth defects with maternal infection but reports in other developing countries where outbreaks occurred were not fully characterized. This study aims to review current reports on birth outcomes associated with maternal ZIKV infection .Zika Virus became an emerging health threat in the early 21This narrative review evaluated birth outcomes of Zika positive pregnant women. Research articles were found using Google Scholar, PubMed, and MEDLINE. The inclusion criteria were publication between 2012 to 2022, availability as full text in English, categorization as original research, meta-analyses or case reports. Exclusion criteria were studies that were part of a book chapter or encyclopedia and studies that cited results from developed nations. The articles were studied and 20 methodologically sound studies were selected for review, and the data was classified in themes based on birth outcomes.18 studies reported that infants born to some laboratory-confirmed zika-positive mothers had abnormal birth outcomes after delivery including microcephaly, stillbirth, neurological abnormalities and hearing loss. Maternal ZIKV infection is associated with an increased risk of abnormal birth outcomes in newborns in developing countries. In the countries of studies that did not report abnormal outcomes there may have been a protective factor from previous maternal Dengue Virus (DENV) infection adding protection for their infants.Overall, there appears a difference in birth outcomes of infants born to mothers infected with ZIKV, however more research is needed on environmental factors and prior arboviral infection as additional factors contributing to these outcomes.All Authors: No reported disclosures