Term Low Birth Weight Research Articles

Prematurity and Congenital Heart Disease: A Contemporary Review.

Congenital heart disease (CHD) is the most commonly reported birth defect in newborns. Neonates with CHD are more likely to be born prematurely, and a higher proportion of preterm neonates have CHD than their term counterparts. The implications of preterm birth on the cardiac and noncardiac organ systems are vast and require special management considerations. The feasibility of surgical interventions in preterm neonates is frequently limited by patient size and delicacy of immature cardiac tissues. Thus, special care must be taken when considering the appropriate timing and type of cardiac intervention. Despite improvements in neonatal cardiac surgical outcomes, preterm and early term gestational ages and low birthweight remain important risk factors for in-hospital mortality. Understanding the risks of early delivery of neonates with prenatally diagnosed CHD may help guide perioperative management in neonates who are born preterm. In this review, we will describe the risks and benefits of early delivery, postnatal cardiac and noncardiac evaluation and management, surgical considerations, overall outcomes, and future directions regarding optimization of perinatal evaluation and management of fetuses and preterm and early term neonates with CHD.

Advanced parental age is an independent risk factor for term low birth weight and macrosomia.

We aimed to investigate association between parental age and the risks of term low birth weight and macrosomia.This was a retrospective cohort study using a national database including 2,245,785 term singleton live births with complete parental age data. Old parental age was defined as 35 years or older. Odd ratios (OR) for term low birth weight and macrosomia were analyzed using univariate and multivariate logistic regression analysis.Neonatal sex, maternal occupation, parity, nationality, age, and paternal age were significant factors of term low birth weight and macrosomia, in univariate analysis. In multivariate analysis, old maternal age (≥35 years old) showed increased odds of term low birth weight and macrosomia (aOR = 1.122, 95% CI: 1.083 –1.162; and aOR = 1.166, 95% CI: 1.143 – 1.189, respectively). Similarly, old paternal age (≥35 years old) showed increased odds of term low birth weight and macrosomia (aOR = 1.090, 95% CI: 1.058 –1.122; and aOR = 1.101, 95% CI: 1.083 – 1.119, respectively). Maternal education that lasted more than 12 years had reduced odds of term low birth weight and macrosomia (OR = 0.817, 95% CI: 0.792 –0.842; and OR = 0.894, 95% CI: 0.879 – 0.91, respectively). Paternal education that lasted more than 12 years also had reduced odds of term low birth weight and macrosomia (OR = 0.865, 95% CI: 0.84 –0.892; and OR = 0.897, 95% CI: 0.881 – 0.913, respectively).This study suggests that not only maternal age but also paternal age are significantly associated with term low birth weight and macrosomia. In addition, parental education levels are also associated with term low birth weight and macrosomia.

Interactive effects of maternal exposure to chemical fertilizer and socio-economic status on the risk of low birth weight

BackgroundMaternal exposure to chemical fertilizer and disadvantaged maternal socio-economic status (SES) have been found to associate with increased risk of low birth weight (LBW). However, whether the two factors would interact to elevate the risk of LBW remains unknown. The present study aimed to explore the interactive effects of maternal exposure to chemical fertilizer during pregnancy and low SES on the risk of term LBW (tLBW).MethodsIn this population-based case–control study, 179 tLBW cases (birthweight < 2500 g and gestational age ≥ 37 weeks) and 204 controls (birthweight ≥ 2500 g and gestational age ≥ 37 weeks) were chosen from the Perinatal Health Care Surveillance System of Pingding County, Shanxi Province, China between 2007 and 2012. Data on basic socio-demographic, dietary and lifestyle characteristics and environmental exposure were directly extracted from the system. Maternal exposure to chemical fertilizer was measured at both household level and village level. Household-level exposure was indicated by household chemical fertilizer use in farming during pregnancy and the data was collected by trained healthcare workers after the selection of cases and controls in 2013. Village-level exposure was indicated by annual amount of village chemical fertilizer consumption per acre and the data came from the Annals of National Economics Statistics of Pingding County in 2010. Interactions between maternal exposure to chemical fertilizer and SES were assessed in logistic regressions using relative excess risk due to interaction (RERI), which indicates an additive interaction if larger than 0.ResultsThe combination of low maternal SES and high exposure to village-level chemical fertilizer consumption was associated with increased risk of tLBW (aOR = 2.62, 95%CI: 1.44 ~ 4.77); The combination of low maternal SES and exposure to household chemical fertilizer use was associated with elevated risk of tLBW (aOR = 2.18, 95%CI: 1.24 ~ 3.83). Additive interactions were detected between high exposure to village-level chemical fertilizer consumption and low maternal SES (RERI:1.79, P < 0.001) and between exposure to household chemical fertilizer use and low maternal SES (RERI:0.77, P < 0.05).ConclusionsOur study suggested negative impacts of potential agricultural pollutants on adverse pregnancy outcomes, especially in disadvantaged socio-economic populations.

Maternal Risk Factors Related with Term Low Birth Weight

Introduction: Low birth weight (LBA) remains to be an important community health issue globally. There are many fetal and maternal factors that contribute to low birth weight. The risk factors of maternal side are socially and biologically related. Low birth weight mortality can be condensed if risk factors from maternal side are perceived primarily and treated through simple procedures. Aim: This research was held to investigate maternal risk factors related with low birth weight. Study Design: A record-based retrospective and case control study. Place and Duration: In the Obstetrics and Gynecology department of Lahore General Hospital for six-months duration from 21st June 2021 to 20th December 2021. Methods: A retrospective, document-based, case-control study was conducted. The collection of retrospective data was performed on the basis of medical records from the department of the Obstetrics and Gynecology. Afterwards the criteria of exclusion and reviewing the integrity of the records, 80 subjects in patients’ group and 80 in control group were included with gestation age of more than 37-weeks. In Microsoft Excel; the data was entered and SPSS 23.0 was applied for data analysis. The chi-square test, student's t-test and odds ratio were applied to identify associated factors result in low birth weight. Results: 80 cases and 80 control groups were examined in this study. The mothers mean age in the study group was 25.1 ± 5.2 years and 23.1 ± 4.28 years in the control group. The patients mean weight was 61.8±6.91 kg in the patient’s group and 64.48±8.60 kg in the control group. The pregnancy-related diseases were noted 37.5% in the patient’s group and 32.5% in the controls group. Conclusion: Maternal factors such as socioeconomic status, haemoglobin, weight, and number of deliveries were related significantly with LBW. Maternal ailments, such as high blood pressure and diabetes, can result in a low birth weight. Keywords: Low birth weight, Maternal factors.

Adverse perinatal outcomes associated with HAART and monotherapy.

Assess adverse perinatal outcomes in pregnant women living with HIV (WLHIV) receiving HAART or zidovudine (ZDV) monotherapy, compared with antiretroviral therapy (ART)-naive WLHIV and HIV-negative women. Systematic review and meta-analysis. We conducted a systematic literature review by searching PubMed, CINAHL, Global Health, and EMBASE for studies published between 1 January 1980 and 20 April 2020. We included studies reporting on the association of pregnant WLHIV receiving HAART or ZDV monotherapy with 11 perinatal outcomes: preterm birth (PTB), very PTB, spontaneous PTB (sPTB), low birth weight (LBW), very LBW, term LBW, preterm LBW, small for gestational age (SGA), very SGA (VSGA), stillbirth, and neonatal death. Random-effects meta-analyses were conducted. Sixty-one cohort studies assessing 409 781 pregnant women were included. WLHIV receiving ZDV monotherapy were associated with a decreased risk of PTB [relative risk 0.70, 95% confidence interval (CI) 0.62-0.79] and LBW (0.77, 0.67-0.88), and comparable risk of SGA, compared with ART-naive WLHIV. WLHIV receiving ZDV monotherapy had a comparable risk of PTB and LBW, and an increased risk of SGA (1.16, 1.04-1.30) compared with HIV-negative women. In contrast, WLHIV receiving HAART were associated with a comparable risk of PTB and LBW, and increased risk of SGA (1.38, 1.09-1.75), compared with ART-naive WLHIV. WLHIV receiving HAART were associated with an increased risk of PTB (1.55, 1.38-1.74), sPTB (2.09, 1.48-2.96), LBW (1.79, 1.51-2.13), term LBW (1.88, 1.23-2.85), SGA (1.80,1.34-2.40), and VSGA (1.22, 1.10-1.34) compared with HIV-negative women. Pregnant WLHIV receiving HAART have an increased risk of a wide range of perinatal outcomes compared with HIV-negative women.

Effects of inter-pregnancy intervals on preterm birth, low birth weight and perinatal deaths in urban South Ethiopia: a prospective cohort study

BackgroundPreterm birth, low birth weight and perinatal deaths are common adverse perinatal outcomes that are linked with each other, and a public health problems contributing to neonatal mortality, especially in developing countries. Although more than half of women in Ethiopia become pregnant within a short interval after the preceding childbirth, whether the short intervals increase the risk of adverse perinatal outcomes or not is understudied. We, therefore, aimed to assess the effects of inter-pregnancy intervals (IPIs) on the adverse perinatal outcomes.MethodsA community-based prospective cohort study was conducted among 2578 pregnant women in urban South Ethiopia. Pregnant women with IPIs < 24 months (IPIs < 18 and 18–23 months) were exposed groups, and those with IPI 24–60 months were the unexposed group. A multilevel analysis (mixed-effects) was done to estimate the effect of IPIs on preterm birth and low birth weight, and a generalized linear model for a binary outcome (fixed-effect) was done for perinatal deaths, using a 95% confidence level.ResultsIn this study, IPI < 18 months found to increase the risk of preterm birth (Adjusted Relative Risk (ARR) = 1.35, 95% CI: 1.02, 1.78), term low birth weight (ARR = 2.20, 95% CI: 1.35, 3.58) and perinatal deaths (ARR = 3.83, 95% CI: 1.90, 7.71) than 24–60 months. The results suggest that, about 9% of preterm birth, 21% of term low birth weight and 41% of perinatal deaths in the study population were attributed to IPI < 18 months. These could be prevented with the removal of the IPI < 18 months in the study population. IPI 18–23 months has shown no effect on the three adverse perinatal outcomes.ConclusionThis study has shown that, IPI under 18 months has a higher risk of adverse perinatal outcomes than IPI 24–60 months. Due attention should still be given for spacing pregnancies.

Both parents matter: a national-scale analysis of parental race/ethnicity, disparities in prenatal PM2.5 exposures and related impacts on birth outcomes.

BackgroundMost U.S. studies that report racial/ethnic disparities in increased risk of low birth weight associated with air pollution exposures have been conducted in California or northeastern states and/or urban areas, limiting generalizability of study results. Few of these studies have examined maternal racial/ethnic groups other than Non-Hispanic Black, non-Hispanic White and Hispanic, nor have they included paternal race. We aimed to examine the independent effects of PM2.5 on birth weight among a nationally representative sample of U.S. singleton infants and how both maternal and paternal race/ethnicity modify relationships between prenatal PM2.5 exposures and birth outcomes.MethodsWe used data from the Early Childhood Longitudinal Study, Birth Cohort (ECLS–B), a longitudinal nationally representative cohort of 10,700 U.S. children born in 2001, which we linked to U.S.EPA’s Community Multi-scale Air Quality (CMAQ)-derived predicted daily PM2.5 concentrations at the centroid of each Census Bureau Zip Code Tabulation Area (ZCTA) for maternal residences. We examined relationships between term birthweight (TBW), term low birthweight rate (TLBW) and gestational PM2.5 pollutant using multivariate regression models. Effect modification of air pollution exposures on birth outcomes by maternal and paternal race was evaluated using stratified models. All analyses were conducted with sample weights to provide national-scale estimates.ResultsThe majority of mothers were White (61%). Fourteen percent of mothers identified as Black, 21% as Hispanic, 3% Asian American and Pacific Islander (AAPI) and 1% American Indian and Alaskan Native (AIAN). Fathers were also racially/ethnically diverse with 55% identified as White Non-Hispanic, 10% as Black Non-Hispanic, 19% as Hispanic, 3% as AAPI and 1% as AIAN. Results from the chi-square and ANOVA tests of significance for racial/ethnic differences indicate disparities in prenatal exposures and birth outcomes by both maternal and paternal race/ethnicity. Prenatal PM2.5 was associated with reduced birthweights during second and third trimester and over the entire gestational period in adjusted regression models, although results did not reach statistical significance. In models stratified by maternal race and paternal race, one unit increase in PM2.5 was statistically significantly associated with lower birthweights among AAPI mothers, -5.6 g (95% CI:-10.3, -1.0 g) and AAPI fathers, -7.6 g (95% CI: -13.1, -2.1 g) during 3rd trimester and among births where father’s race was not reported, -14.2 g (95% CI: -24.0, -4.4 g).ConclusionsThese data suggest that paternal characteristics should be used, in addition to maternal characteristics, to describe the risks of adverse birth outcomes. Additionally, our study suggests that serious consideration should be given to investigating environmental and social mechanisms, such as air pollution exposures, as potential contributors to disparities in birth outcomes among AAPI populations. Supplementary InformationThe online version contains supplementary material available at 10.1186/s12940-022-00856-w.

Is limited access to obstetric services associated with adverse birth outcomes? A cross-sectional study of Korean national birth data

ObjectivesThe geographical disparity in the access to essential obstetric services is a public health issue in many countries. We explored the association between timely access to obstetric services and the...

Assessing the effect of fine particulate matter on adverse birth outcomes in Huai River Basin, Henan, China, 2013–2018

Previous studies have indicated that maternal exposure to particles with aerodynamic diameter <2.5 μm (PM2.5) is associated with adverse birth outcomes. However, the critical exposure windows remain inconsistent. A retrospective cohort study was conducted in Huai River Basin, Henan, China during 2013–2018. Daily PM2.5 concentration was collected using Chinese Air Quality Reanalysis datasets. We calculated exposures for each participant based on the residential address during pregnancy. Binary logistic regression was used to examine the trimester-specific association of PM2.5 exposure with preterm birth (PTB), low birth weight (LBW) and term LBW (tLBW), and we further estimated monthly and weekly association using distributed lag models. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for each 10 μg/m3 increase in PM2.5 exposure. Stratified analyses were performed by maternal age, infant gender, parity, and socioeconomic status (SES). In total, 196,780 eligible births were identified, including 4257 (2.2%) PTBs, 3483 (1.8%) LBWs and 1770 (0.9%) tLBWs. Maternal PM2.5 exposure during the second trimester were associated with the risk of PTB and LBW. At the monthly level, the PTB and LBW risks were associated with PM2.5 exposure mainly in the 4th -6th month. By estimating the weekly-specific association, we observed that critical exposure windows of PM2.5 exposure and PTB were in the 18th- 27th gestational weeks. Stronger associations were found in younger, multiparous mothers and those with a female baby and in low SES. In conclusion, the results indicate that maternal PM2.5 exposure during the second trimester was associated with PTB and LBW. Younger, multiparous mothers and those with female babies and in low SES were susceptible.

Associations between seasonal ambient air pollution and adverse perinatal outcomes: a retrospective cohort study in Wenzhou, China.

Prenatal exposure to ambient air pollution has been associated with adverse perinatal outcomes in previous studies. However, few studies have examined the interaction between air pollution and the season of conception on term low birth weight (TLBW) or macrosomia. Birth registry data of singleton live births in Wenzhou, China, between January 2015 and December 2016 were accessed from the Wenzhou Maternal and Child Health Information Management platform, and data on the ambient air pollutants in Wenzhou were obtained from the Chinese Air Quality Online Monitoring and Analysis Platform. Single-/two-pollutant binary logistic regression models were used to assess the associations between ambient air pollutants (PM2.5, PM10, NO2, SO2, and O3) and TLBW/macrosomia, further exploring whether the season of conception interacts with air pollution to impact birth weight. Finally, 213,959 term newborns were selected, including 2452 (1.1%) infants with TLBW and 13,173 (6.1%) infants with macrosomia. In the single-/two-pollutant models, we observed an increased risk of TLBW associated with maternal exposure to PM2.5, PM10, SO2, and NO2 during the entire pregnancy, especially in the 2nd trimester. Maternal exposure to O3 during the 1st trimester was associated with increased macrosomia risk, and O3 exposure during the 3rd trimester was associated with increased TLBW risk. Pregnant women who conceive in the warm season may experience a more adverse ambient air environment that is related to the risks of TLBW. These findings add to the evidence suggesting that air pollution and the season of conception may have synergistic effects on adverse perinatal outcomes, especially TLBW. Further prospective cohort studies are needed to validate our results.

Adverse perinatal outcomes associated with protease inhibitor-based antiretroviral therapy in pregnant women living with HIV: A systematic review and meta-analysis

SummaryBackgroundThe World Health Organization recommends protease inhibitor (PI)-based antiretroviral therapy (ART) as second-line and third-line regimens in pregnant women living with HIV (WLHIV). US, European, and UK guidelines include PI-based ART as first-line regimens, but advise against the use of lopinavir/ritonavir (LPV/r)-based ART, citing an increased risk of preterm birth (PTB). We aimed to assess the risk of adverse perinatal outcomes in WLHIV receiving PI-ART and the comparative risks associated with different PI-ART regimens.MethodsWe conducted a systematic literature review by searching PubMed, CINAHL, Global Health, and EMBASE for studies published between Jan 1, 1980, and April 20, 2020. Two investigators independently selected studies and extracted data from studies reporting on the association of pregnant WLHIV receiving PI-ART with 11 perinatal outcomes: PTB, very PTB (VPTB), spontaneous PTB (sPTB), low birth weight (LBW), very LBW (VLBW), term LBW, preterm LBW, small for gestational age (SGA), very SGA (VSGA), stillbirth, and neonatal death. Pairwise random-effects meta-analyses examined the risk of each adverse perinatal outcome in WLHIV receiving PI-ART compared to non-PI-based ART (non-PI-ART), and comparisons of different PI-ART regimens. Quality assessments of studies were performed, subgroup and sensitivity analyses were conducted based on country income status and study quality, heterogeneity assessed, and the effect of adjustment for confounding factors assessed. The protocol is registered with PROSPERO, CRD42021248987.FindingsOf 94,594 studies identified, 34 cohort studies including 57,546 women met the inclusion criteria. Random-effects meta-analyses showed that PI-ART was associated with a significantly increased risk of SGA (Relative Risk [RR] 1.24, 95% CI 1.08–1.43; I2=66.7%) and VSGA (RR 1.40, 1.09–1.81; I2=0.0%), but not PTB (RR 1.09, 0.95–1.24; I2=68.3%), VPTB (RR 1.30, 0.78–2.18; I2=43.0%), sPTB (RR 1.91, 0.61–5.99; I2=95.7%), LBW (RR 1.04, 0.85–1.27; I2=63.9%), VLBW (RR 0.72, 0.37–1.43; I2=37.9%), term LBW (RR 0.94, 0.30–3.02; I2=0.0%), stillbirth (RR 1.04, 0.60–1.79; I2=0.0%), and neonatal death (RR 1.82, 0.97–3.40; I2=0.0%), compared to non-PI-ART. We found no significant differences in perinatal outcomes between ART regimens containing LPV/r, atazanavir/ritonavir (ATV/r), and darunavir/ritonavir (DRV/r), which are the most commonly used PIs.InterpretationPI-ART is associated with an increased risk of SGA and VSGA, but not PTB or other perinatal outcomes. No significant differences in perinatal outcomes were found between LPV/r, ATV/r, and DRV/r. These findings should inform clinical guidelines, and further efforts should be made to improve perinatal outcomes among pregnant WLHIV.FundingNone.

The effect and its critical window for ambient temperature and humidity in pregnancy on term low birth weight.

As common meteorological factors in daily life, there is limited evidence for the effect of ambient temperature and humidity during pregnancy on the risk of term low birth weight. Furthermore, little is known about the interaction of ambient temperature and humidity on TLBW. The objective of the study was to explore the effect of ambient temperature, humidity during pregnancy, and their interaction on the risk of TLBW and, moreover, to identify exposure critical window. We recruited 6640 infants and their mothers to build a birth cohort study in Jinan City, China, from January 2018 to December 2019. The associations between temperature and humidity during pregnancy and TLBW were estimated by generalized additive model, logistic regression model, and interaction analysis, and the critical window was identified by the distributed lag non-linear model. The incidence of TLBW was 1.36% for the infants in the birth cohort. TLBW was related to the low level of temperature and humidity in the whole pregnancy, compared with the moderate level and the adjusted ORs were 4.44 (1.65-11.42) and 6.23 (1.92-21.39), respectively. The indicators of the interaction analysis of temperature and humidity were not statistically significant. For the low level of humidity, the association with TLBW was statistically significant at first to sixth gestational weeks, and the maximum OR in male infants (3.95, 1.70-9.16) was higher than that in females (1.96, 1.06-3.63). For the low level of temperature, we failed to find significant association with TLBW at each gestational week. The low level of temperature and humidity during pregnancy could increase the risk of TLBW. There was no statistical interaction between temperature and humidity on TLBW. Moreover, the early stage of pregnancy was the critical window for humidity exposure, in which the boys had a greater effect.

Abstract 107: Klinefelter's syndrome presenting with ambiguous genitalia

A first-born child born out of non-consanguinity, with term delivery and low birth weight was brought at 1 year 4 months of age with left undescended testis and ambiguity. Antenatal, perinatal and developmental history were uneventful. There was no h/o failure to thrive or generalized hyperpigmentation. On examination there was bifid scrotum with rugosities and palpable testis on the right with left testis in the inguinal canal. The shaft measured 2 cm with penoscrotal hypospadias. On evaluation the stimulated T: DHT was 127.3 and T: A was 13.42, suggestive of 5-alpha reductase deficiency. However, the karyotyping revealed 47XXY karyotype. Clinical exome sequencing did not reveal any mutations. Ambiguity is a rare presentation in patients with Klinefelter's syndrome.

Differences in Rates of Low Birth Weight among Prefectures in Japan: An Ecological Study Using Government Statistics Data.

The differences in the rates and trends of the overall low birth weight and term low birth weight in recent years are unknown for the Japanese prefectures. In this ecological study, we revealed the rates for each prefecture and investigated the factors affecting the regional differences in these outcomes. Aggregated vital statistics data from 2007 to 2019 were obtained from the Ministry of Health, Labour, and Welfare in Japan. The association between the outcomes and the variables, including the infants’ birth characteristics, medical characteristics, and socioeconomic characteristics of the prefectures, were analyzed. An analysis of repeated-measures data was conducted using the data from 2013 and 2018 for each prefecture. The trend for the rates of overall low birth weight and term low birth weight over the years differed among the prefectures. Moreover, the proportions of multiple births and lean (body mass index <18.5 kg/m2) and obese (body mass index ≥25.0 kg/m2) women had a statistically significant positive association with both the overall low birth weight rate and the term low birth weight rate among the prefectures. It was suggested that to resolve the difference in these outcomes among the prefectures, being obese or underweight needs to be addressed in mothers.

Mother-level random effect in the association between PM2.5 and fetal growth: A population-based pregnancy cohort

BackgroundA growing body of literature reports associations between exposure to particulate matter with diameter ≤2.5 μm (PM2.5) during pregnancy and birth outcomes. However, findings are inconsistent across studies. ObjectivesTo assess the association between PM2.5 and birth outcomes of fetal growth in a cohort with high prevalence of siblings by multilevel models accounting for geographical- and mother-level correlations. MethodsIn Israel, we used Maccabi Healthcare Services data to establish a population-based cohort of 381,265 singleton births reaching 24–42 weeks’ gestation and birth weight of 500–5000 g (2004–2015). Daily PM2.5 predictions from a satellite-based spatiotemporal model were linked to the date of birth and maternal residence. We generated mean PM2.5 values for the entire pregnancy and for exposure periods during pregnancy. Associations between exposure and birth outcomes were modeled by using multilevel logistic regression with random effects for maternal locality of residence, administrative census area (ACA) and mother. ResultsIn fully adjusted models with a mother-level random intercept only, a 10-μg/m3 increase in PM2.5 over the entire pregnancy was positively associated with term low birth weight (TLBW) (Odds ratio, OR = 1.25, 95% confidence interval, CI: 1.09,1.43) and small for gestational age (SGA) (OR = 1.15, 95% CI: 1.06,1.26). Locality- and ACA-level effects accounted for <0.4% of the variance while mother-level effects explained ∼50% of the variability. Associations varied by exposure period, infants’ sex, birth order, and maternal pre-pregnancy BMI. ConclusionsConsideration of mother-level variability in a region with high fertility rates provides new insights on the strength of associations between PM2.5 and birth outcomes.

Effects of household environmental exposure and ventilation in association with adverse birth outcomes: A prospective cohort study in rural China

Prenatal exposure to outdoor air pollution have been associated with birth outcomes. However, there is limited evidence on the adverse effects of household indoor air pollution worldwide, much less in rural areas of China. This study aimed to explore the associations of household environmental factors (primary cooking fuel, housing renovation, and home ventilation) with four adverse birth outcomes (preterm birth (PTB), small for gestational age (SGA), low birth weight (LBW), and term low birth weight (T-LBW)). We conducted a cohort study involving 10,324 pregnancies in women who delivered a live-born infant from 2015 to 2018 in Guangxi, China. Risk ratios and 95% confidence intervals (CI) were estimated with control for reproductive history, lifestyle, home environmental confounders, and other potential confounders. A total of 5.4% of the infants were PTB, 10.7% were SGA, 5.5% had LBW, and 3.0% had T-LBW. Household-use induction cookers as the primary cooking fuel during pregnancy was associated with SGA (RR = 1.31, 95% CI: 1.07–1.60), LBW (1.41, 1.09–1.82), and T-LBW(1.62, 1.16–2.26), as compared with household-use gas as the primary cooking fuel. Housing renovation within one year before pregnancy was associated with PTB (1.45, 1.06–1.98) and LBW (1.56, 1.17–2.09), while housing renovation during pregnancy was associated with a higher risk of SGA only in moderate home ventilation conditions (3.74, 1.69–8.28). Our findings suggested that household-use induction cookers as the primary cooking fuel increased the risks of SGA, LBW, and T-LBW. In addition, housing renovation within one year before pregnancy increased the risks of PTB and LBW. Proper home ventilation may reduce the effect on the association between housing renovation during pregnancy and SGA.

Lifetime cardiovascular risk factors and maternal and offspring birth outcomes: Bogalusa Babies.

Both cardiovascular and reproductive complications may have origins in utero or in early life. Women in the Bogalusa Heart Study (n = 1401) had been linked to birth certificates for birthweight and gestational data, which were examined relative to childhood (ages 4–16) cardiometabolic indicators, indicated by mean levels overall and total risk factor burden as estimated by area under the curve (AUC) computed from longitudinal quadratic random-effects growth models. Women reported the birthweight and gestational age of each of their own pregnancies, and delivery medical records were linked to interview data where possible. Path analyses were conducted to examine the relationships among a woman’s own birth outcomes, childhood and preconception adult cardiovascular health, and birth outcomes. Mean blood pressure (systolic blood pressure (SBP) adjusted relative risk (aRR) per 1-SD increase, 1.27, 95% CI 1.04–1.57) and low-density lipoprotein (aRR 1.21, 95% CI 1.02–1.44) in childhood predicted preterm birth (PTB), while mean SBP (aRR 1.33, 95% CI 1.02–1.74) predicted term low birthweight. The AUC data suggested an association between blood pressure and PTB (aRR for SBP top 10%, 1.86, 95% CI 1.08–3.21). Pre-pregnancy total cholesterol was negatively associated with gestational age. In path analyses, positive associations were found for each step between own birthweight, childhood BMI, pre-pregnancy BMI, and child’s birthweight. Childhood levels of some, though not all, cardiovascular risk factors may predict adverse birth outcomes (preterm birth and reduced fetal growth).

Low and High Ambient Temperatures during Pregnancy and Birth Weight among 624,940 Singleton Term Births in Israel (2010–2014): An Investigation of Potential Windows of Susceptibility

Background:Exposure to heat during pregnancy has been associated with reduced fetal growth. Less is known about associations with cold and the potential for critical time windows of exposure.Objectives:We aimed to evaluate, in a national retrospective cohort, critical windows of susceptibility during pregnancy to extreme temperatures (low and high) and fetal growth, among 624,940 singleton term births in Israel during the period 2010–2014.Methods:Temperature exposures were estimated using a spatially refined gridded climate data set with a 1-h and resolution. Percentiles of temperature were categorized by climatic zone for the entire pregnancy and by trimesters and weeks. Generalized additive models with the distributed lag nonlinear model framework were used to estimate unadjusted and adjusted associations between percentiles and categories of temperature and fetal growth markers: term [births after 36 weeks of gestational age (GA)] mean birth weight and term low birth weight (tLBW, term infants with birth weight below ).Results:After adjustment, extreme temperatures (percentiles) during the entire pregnancy were associated with a lower mean birth weight { vs. 41st–50th percentile: [95% confidence interval (CI): , )]; vs. 41st–50th percentile: ; 95% CI: , }. Similar inverse U-shaped patterns were observed for all trimesters, with stronger associations for heat than for cold and for exposures during the third trimester. For heat, results suggest critical windows between 3–9 and 19–34 GA-weeks, with the strongest association estimated at 3 GA-weeks (temperature vs. 41st–50th percentiles: ; 95% CI: , ). For cold, there was a consistent trend of null associations early in pregnancy and stronger inverse associations over time, with the strongest association at 36 GA-week ( vs. 41st–50th percentiles: ; 95% CI: , ). For tLBW, U-shape patterns were estimated for the entire pregnancy and third trimester exposures, as well as nonsignificant associations with heat for 29–36 GA-weeks. Generally, the patterns of associations with temperatures during the entire pregnancy were consistent when stratified by urbanicity and geocoding hierarchy, when estimated for daily minimum and maximum temperatures, when exposures were classified based on temperature distributions in 49 natural regions, and when estimated for all live births.Discussion:Findings from our study of term live births in Israel (2010–2014) suggest that exposure to extreme temperatures, especially heat, during specific time windows may result in reduced fetal growth. https://doi.org/10.1289/EHP8117

66Adverse birth outcomes associated with ambient air pollution at levels below air quality guidelines

Abstract Background Gaps exist concerning the relationship between maternal exposure to air pollution and birth outcomes, including the importance of low-level exposure. We aimed to explore the association between maternal exposure to ambient nitrogen dioxide (NO2) and fine particulate matter (PM2.5) and selected birth outcomes in Victoria, Australia. Methods We included all births occurring in Victoria, Australia from 1st March 2012 to 31st December 2015 using routinely collected government data. Outcomes included birthweight, small for gestational age (SGA), term low birth weight (tLBW), large for gestational age, and spontaneous preterm birth. Annual ambient NO2 and PM2.5 was assigned to maternal residence at birth. Maternal, meteorological and temporal variables were included in final log-binomial models. Results There were 285,594 births. Average annual ambient NO2 exposure was 6.0 parts per billion (ppb, IQR 3.9 ppb) and PM2.5 was 6.9 µg/m3 (IQR 1.3). IQR increases in ambient NO2 and PM2.5 were associated with fetal growth restriction, including decrements in birth weight, increased risk of SGA and tLBW. Women with gestational diabetes and hypertensive disorders of pregnancy had greater decrements in birth weight associated with exposure. Conclusions Maternal exposure to low-level ambient air pollution at levels below national and international air quality guidelines was associated with fetal growth restriction. Key messages Exposure to low-level ambient air pollution was associated with fetal growth restriction and women with obstetric complications were more susceptible. These findings may inform iterative revisions of air quality guidelines.

68Maternal exposure to PM2.5 from a severe smoke event and birth outcomes in Victoria, Australia

Abstract Background The 2014 Hazelwood coal mine fire was an unprecedented six-week severe smoke event in the Latrobe Valley, southeastern Australia. We aimed to determine whether maternal exposure to fine particulate matter (PM2.5) attributable to the event was associated with adverse fetal growth or maturity, including birthweight, small for gestational age, term low birthweight or preterm birth. Methods A cohort of babies born within the affected region was defined used administrative perinatal data. Maternal average and peak PM2.5 was assigned to residential address at time of delivery using a chemical transport model. Maternal, infant, meteorological and temporal variables were included in final linear and log-binomial regression models. Results 3,591 singleton livebirths were included; 763 were exposed in utero. Average PM2.5 exposure was 4.4 µg/m3 (IQR 2.1 µg/m3); average peak was 45.0 µg/m3 (IQR 35.1 µg/m3). No association between PM2.5 and fetal growth or maturity was observed. Gestational diabetes mellitus was an effect modifier in the relationship; babies of exposed gestational diabetic mothers were 97 grams heavier per 10 µg/m3 increase in average PM2.5 exposure (95%CI 74, 120 grams), compared to mothers without gestational diabetes. Conclusions Maternal PM2.5 exposure from a smoke event was not associated with adverse fetal growth or maturity. There was a trophic response amongst babies of mothers with gestational diabetes. Key messages Babies born to mothers with gestational diabetes may be more susceptible to the effects of smoke events on birthweight.