The association between ambient air pollution and selected adverse pregnancy outcomes in China: A systematic review

Meta-analysis of fine particulate matter exposure during pregnancy and birth weight: Exploring sources of heterogeneity

BACKGROUND

Several meta-analyses assessed the relationship between exposure to PM with aerodynamic diameter ≤ 2.5 μm (PM2.5) during pregnancy and birth weight (BW), but results were inconsistent and substantial unexplained heterogeneity was reported. We aimed to investigate the above association and to explore sources of heterogeneity across studies.

METHODS

We systematically reviewed the current worldwide evidence examining the association between PM2.5 and BW. The review protocol was registered on the PROSPERO website (CRD42020188996) and followed PRISMA guidelines. We extracted association measures for BW and low birth weight (LBW, BW < 2500 g) from each study to evaluate pooled summary measures and to explore sources of between-study heterogeneity.

FINDINGS

Of the 2677 articles identified, 84 met the inclusion criteria (~42 M births). Our random effects meta-analyses revealed substantial heterogeneity among included studies (I2 = 98.4 % and I2 = 77.7 %, for BW and LBW respectively). For LBW, the heterogeneity decreased (I2 = 59.7 %) after excluding four outlying studies, with a pooled odds ratio 1.07 (95 % confidence interval, CI: 1.05, 1.09) per a 10-μg/m3 increase in mean PM2.5 exposure over the entire pregnancy. Further subgroup analysis revealed geographic heterogeneity with higher association in Europe (1.34, (1.16, 1.55)) compared to Asia (1.06, (1.03, 1.10)) and US (1.07, (1.04, 1.10)).

CONCLUSION

The association between PM2.5 and birth weight varied depending on several factors. The sources of heterogeneity between studies included modifiers such as study region and period. Hence, it is advisable not to pool summary measures of PM2.5-BW associations and that policy would be informed by local evidence.

Windows of sensitivity for risk of adverse birth outcomes related to gestational PM2.5 exposure: Evidence from a natural experiment

While numerous studies have associated maternal exposure to PM2.5 with adverse birth outcomes, findings remain inconsistent and difficult to generalize. We aimed to investigate the causal relationship and window of sensitivity between gestational exposure to PM2.5 and birth outcomes. We leveraged high-resolution satellite data to quantify gestational PM2.5 exposure at the individual level, along with a combined model to determine daily relative risks (RRs) of birth outcomes in COVID-19 prelockdown and lockdown groups. RRs between the two groups were further compared using a longitudinal pre-post non-experimental design to identify sensitivity windows of adverse birth outcomes. A total of 73,781 pregnant women from the COVID-19 prelockdown group and 6267 pregnant women from the lockdown group were included for analysis. The daily mean PM2.5 concentrations in the lockdown group decreased by 21.7% compared to the prelockdown group. During the first trimester, every 10 μg/m3 increase in PM2.5 significantly increased the risk of congenital abnormalities of major organs such as the cardiovascular system, gastrointestinal tract, nervous system, urinary system, and respiratory system. Moreover, gestational exposure to PM2.5 during the first trimester was associated with higher risks of premature delivery and term low birth weight. While PM2.5 exposure during the second trimester was positively correlated with macrosomia. Gestational exposure to PM2.5 is associated with increased risks of various adverse birth outcomes with specific sensitive windows. We demonstrated that gestational exposure to PM2.5 increased risks of various adverse birth outcomes with specific window of sensitivity through the natural experiment design. Our findings underscore the urgent need for policies and initiatives targeting PM2.5 reduction, especially during critical periods of pregnancy.

Traffic safety and public health in China - Past knowledge, current status, and future directions

Transportation-related harms have developed into a social disease, threatening public safety and health in China. We aimed to increase the global understanding of traffic safety and public health in China from past knowledge, current status, and future directions by collecting, collating, and analyzing the Chinese traffic incidents reported in the published literature. A systematic search of China National Knowledge Infrastructure, Weipu, and published articles referenced in PubMed, Web of Science and ProQuest between January 1, 1988 and April 30, 2023 was performed. China encountered the first recorded traffic accident as early as three thousand years ago in the Shang Dynasty. An increase in vehicle capacity and velocity increased the traffic risks during the transition from rickshaws and livestock to motor vehicles in varying traffic environments. Humans are not only the decisive factor of a large number of vehicles, traffic routes, and environmental variables, but also the victims at the end and starting point of traffic accidents. Injuries (mechanical force, burns) and diseases (traffic-related air pollution, noise) caused by traffic activities not only threaten public health, but also cause risks to safe driving. Analysis of traffic activities and biomarkers promotes the treatment of traffic injuries in ethology and medicine. China prepared for the construction of healthy transportation in the "decade of road safety" toward an estimation of worldwide road traffic injuries in 2030. Improvement of traffic safety concerning public health under the "Outline of the National Comprehensive Three-dimensional Transportation Network Planning" in China will propel the realization of worldwide traffic environmental advancement.

Association between ambient air pollution exposure in pregnant women with antiphospholipid syndrome in Nanjing, China

Antenatal exposure to air pollutants is thought to be associated with a variety of maternal blood markers as well as adverse birth outcomes. However, the dysgenic influence of air pollutants on the antiphospholipid syndrome (APS) in mothers and their pregnancy outcomes remains unclear. In the current study, 371 mother-infant pairs (189 healthy: 182 APS) from Nanjing Maternal and Child Health Hospital as well as air pollutants concentration from their living environment were used to investigate correlations between air pollution with maternal blood indicators and fetal birth weight in the groups of APS and healthy mothers. Generalized linear model was used to evaluate the contributions of air pollutant exposure during pregnancy to the blood indicators variation. The relationships between birth weight with specific air pollutant and blood index were analyzed using ridge regression. Results showed that APS fetal birth weight was significantly impacted by air pollutant exposure during pregnancy, in particular, the birth weight decreased significantly along with increasing fine particulate matter 2.5 (PM2.5) and fine particulate matter 10 (PM10) exposure concentrations throughout pregnancy. In contrast, birth weight increased significantly with sulfur dioxide (SO2) exposure. In addition, APS-related blood indicators comprised of platelet distribution width (PDW), total bilirubin (TBIL), mean platelet volume (MPV), platelet-larger cell ratio (P_LCR), homocysteine (HCY), alkaline phosphatase (ALP), direct bilirubin (DBIL), basophilic granulocyte (BAS), platelet thrombocytocrit (PCT), preprandial glucose levels (OGTT0), monocytes (MON), and monocytes ratio (MON_ratio) were also strongly related with prenatal exposure to PM2.5 and PM10, in which PDW levels showed most strongly negative impaction on fetal birth weight. Together, we showed that prenatal exposure to air pollutant (PM2.5 and PM10) may exacerbate the poor birth outcomes of low birth weight by impacting APS maternal blood indicators especially for PDW.

Identifying critical windows of air pollution exposure during preconception and gestational period on birthweight: a prospective cohort study

BACKGROUND

Few studies have assessed air pollution exposure association with birthweight during both preconception and gestational periods.

METHODS

Leveraging a preconception cohort consisting of 14220 pregnant women and newborn children in Shanghai, China during 2016-2018, we aim to assess associations of NO2 and PM2.5 exposure, derived from high-resolution spatial-temporal models, during preconception and gestational periods with outcomes including term birthweight, birthweight Z-score, small-for-gestational age (SGA) and large-for-gestational age (LGA). Linear and logistic regressions were used to estimate 3-month preconception and trimester-averaged air pollution exposure associations; and distributed lag models (DLM) were used to identify critical exposure windows at the weekly resolution from preconception to delivery. Two-pollutant models and children's sex-specific associations were explored.

RESULTS

After controlling for covariates, one standard deviation (SD) (11.5 μg/m3, equivalent to 6.1 ppb) increase in NO2 exposure during the second and the third trimester was associated with 13% (95% confidence interval: 2 - 26%) and 14% (95% CI: 1 - 29%) increase in SGA, respectively; and one SD (9.6 μg/m3) increase in PM2.5 exposure during the third trimester was associated with 15% (95% CI: 1 - 31%) increase in SGA. No association have been found for outcomes of birthweight, birthweight Z-score and LGA. DLM found that gestational weeks 22-32 were a critical window, when NO2 exposure had strongest associations with SGA. The associations of air pollution exposure tended to be stronger in female newborns than in male newborns. However, no significant associations of air pollution exposure during preconception period on birthweight outcomes were found.

CONCLUSION

Consistent with previous studies, we found that air pollution exposure during mid-to-late pregnancy was associated with adverse birthweight outcomes.

Effect of short-term ambient air pollution exposure on early miscarriage and pregnancy hormones with critical window identification

BACKGROUND

Pregnancy hormones are particularly important in early miscarriage, and some evidence suggests that exposure to air pollution is associated with pregnancy hormones and miscarriage. However, the effects of air pollution on pregnancy hormone-mediated miscarriages have not yet been investigated.

METHODS

We collected air pollution exposure measurements and pregnancy hormone tests from the participants. Logistic regression models were used to investigate the association between air pollution and early miscarriages. A distributed lag nonlinear model (DLNM) was used to investigate non-linear and delayed associations and identify the crucial window. We performed mediation analysis to estimate the potential association that may exist between pregnancy hormone levels and early miscarriage.

RESULTS

Short-term exposure to CO and SO2 was associated with early miscarriage. Lag 22-28 days of exposure to both CO and SO2 and lag 15-21 days of exposure to CO were significantly positively associated with early miscarriage, with an obvious exposure dose response. Serum progesterone concentration explained 36.79 % of the association between lag 15-28 days of CO exposure and early miscarriage.

CONCLUSION

This study provides evidence for the association between short-term exposure to air pollution and early miscarriage, and provides clues for further exploration of biological mechanisms.

Ambient fine particulate matter and pregnancy outcomes: An umbrella review

The available evidence on the effects of ambient fine particulate matter (PM2.5) and pregnancy outcomes (birth outcomes and pregnancy complications) has increased substantially. The purpose of this umbrella review is to refine the evidence of the association between birth outcome (birth defects) and PM2.5; and summarize the credibility of existing research on the association between pregnancy complications and PM2.5. We searched PubMed, Web of Science, Embase, and Cochrane databases for relevant systematic reviews and meta-analyses up to March 16, 2022 in accordance with PRISMA guidelines. Two independent investigators conducted data extraction. AMSTAR 2 and GRADE assessment criteria were used to evaluate the methodological and evidence quality. We performed subgroup analyses by trimesters of pregnancy. The review protocol for this study has been registered in PROSPERO (CRD42022325550). This umbrella review identified a total of 41 systematic reviews, including 28 articles evaluating the influence of PM2.5 on birth outcomes and 13 on pregnancy complications. Positive associations between perinatal PM2.5 exposure and adverse birth outcomes were found, including low birth weight, preterm birth, stillbirth, small for gestational age, and birth defects. Pregnant women exposed to PM2.5 had a significantly higher risk of developing hypertensive disorder of pregnancy, gestational diabetes mellitus, gestational hypertension, and preeclampsia. The findings of subgroup analysis demonstrated that the effects of ambient PM2.5 exposure on pregnancy outcomes varied by trimesters. The findings of this extensive umbrella review provide convincing proof that exposure to ambient PM2.5 raises the risks of unfavorable birth outcomes and pregnancy complications. Some associations show considerable disparity between trimesters. These findings have implications for strengthen perinatal health care on air pollution and improving intergenerational equity.

Prenatal PM2.5 exposure increases the risk of adverse pregnancy outcomes: evidence from meta-analysis of cohort studies

Adverse pregnancy outcomes (APOs) are a significant cause of fetal death. A wide range of maternal psychological, social, and environmental factors may contribute to these outcomes. Mounting epidemiological studies have indicated that PM2.5 may result in these unfavorable consequences. Previously published meta-analyses have been updated and extended. Cohort studies were searched from three databases (up to July 24, 2023), and their quality was assessed by Newcastle-Ottawa Scale (NOS). Publication bias was examined by Egger's test and funnel plot. Despite a large number of studies showing similar results, the inconsistencies between these findings require careful generalization before concluding. This meta-analysis included 67 cohort studies from 20 countries, and the findings revealed that maternal PM2.5 exposure and five APOs were correlated significantly throughout pregnancy: preterm birth (PTB) (RR = 1.05; 95% CI: 1.03, 1.07); low birth weight (LBW) (RR = 1.02; 95% CI: 1.01, 1.04); small for gestational age (SGA) (RR = 1.03; 95% CI: 1.01, 1.04); stillbirth (RR = 1.24; 95% CI: 1.06, 1.45); and change in birthweight (weight change = -6.82 g; 95% CI: -11.39, -2.25). A positive association was found between APOs and PM2.5 exposure in this meta-analysis, and the degree of increased risk of APOs varied due to different gestation periods. Therefore, it is necessary to protect pregnant women at specific times.

Effects of Air Pollution Exposure during Preconception and Pregnancy on Gestational Diabetes Mellitus

This study aimed to investigate the association between air pollution and gestational diabetes mellitus (GDM) in small- and medium-sized cities, identify sensitive periods and major pollutants, and explore the effects of air pollution on different populations. A total of 9820 women who delivered in Handan Maternal and Child Health Hospital in the Hebei Province from February 2018 to July 2020 were included in the study. Logistic regression and principal component logistic regression models were used to assess the effects of air pollution exposure during preconception and pregnancy on GDM risk and the differences in the effects across populations. The results suggested that each 20 μg/m3 increase in PM2.5 and PM10 exposure during preconception and pregnancy significantly increased the risk of GDM, and a 10 μg/m3 increase in NO2 exposure during pregnancy was also associated with the risk of GDM. In a subgroup analysis, pregnant women aged 30-35 years, nulliparous women, and those with less than a bachelor's education were the most sensitive groups. This study provides evidence for an association between air pollution and the prevalence of GDM, with PM2.5, PM10, and NO2 as risk factors for GDM.

Prenatal exposure to ambient air pollutants and congenital heart defects: An umbrella review

BACKGROUND

Prenatal exposure to ambient air pollutants has been linked to congenital heart defects (CHD), but findings of existing systematic reviews have been mixed.

OBJECTIVE

To assess the epidemiological evidence on associations between prenatal exposure to ambient air pollutants and CHD subtypes, based on a systematic overview of reviews ("umbrella review").

METHODS

We conducted a systematic search for reviews assessing associations between prenatal exposure to criteria air pollutants and CHD. The risk of bias was evaluated using the Risk of Bias in Systematic Reviews (ROBIS) tool. The certainty of the systematic review findings was graded using the Navigation Guide methodology.

RESULTS

We identified eleven systematic reviews, including eight with meta-analyses, assessing in total 35 primary studies of prenatal exposure to criteria air pollutants and various CHD subtypes. The certainty of the findings of four meta-analyses indicating an increased risk for coarctation of the aorta associated with nitrogen dioxide exposure was rated as moderate. The certainty of findings indicating positive, inverse, or null associations for other pollutant-subtype combinations was rated as very low to low, based on low precision and high statistical heterogeneity of summary odds ratios (SOR), substantial inconsistencies between review findings, and methodological limitations of the systematic reviews.

DISCUSSION

The inconsistent findings and high statistical heterogeneity of many SOR of the included systematic reviews may partly be traced to differences in methodological approaches, and the risk of bias across included reviews (e.g., inclusion criteria, systematic search strategies, synthesis methods) and primary studies (e.g., exposure assessment, diagnostic criteria). Adherence to appropriate systematic review guidelines for environmental health research, as well as rigorous evaluation of risk of bias in primary studies, are essential for future risk assessments and policy-making. Still, our findings suggest that prenatal exposure to ambient air pollutants may increase risks for at least some CHD subtypes.

Combined exposure to PM2.5 and PM10 in reductions of physiological development among preterm birth: a retrospective study from 2014 to 2017 in China

Background

Preterm birth (PTB) has been linked with ambient particulate matter (PM) exposure. However, data are limited between physiological development of PTB and PM exposure.

Methods

Trimester and season-specific PM exposure including PM2.5 and PM10 was collected from Jiaxing between January 2014 and December 2017. Information about parents and 3,054 PTB (gestational age < 37 weeks) outcomes such as weight (g), head circumference (cm), chest circumference (cm), height (cm) and Apgar 5 score were obtained from birth records. We used generalized linear models to assess the relationship between PTB physiological developmental indices and PM2.5, PM10 and their combined exposures. A binary logistic regression model was performed to assess the association between exposures and low birth weight (LBW, < 2,500 g).

Results

Results showed that there were 75.5% of low birth weight (LBW) infants in PTB. Decreased PM2.5 and PM10 levels were found in Jiaxing from 2014 to 2017, with a higher PM10 level than PM2.5 each year. During the entire pregnancy, the highest median concentration of PM2.5 and PM10 was in winter (61.65 ± 0.24 vs. 91.65 ± 0.29 μg/m3) followed by autumn, spring and summer, with statistical differences in trimester-specific stages. After adjusting for several potential factors, we found a 10 μg/m3 increase in joint exposure of PM2.5 and PM10 during the entire pregnancy associated with reduced 0.02 week (95%CI: -0.05, -0.01) in gestational age, 7.9 g (95%CI: -13.71, -2.28) in birth weight, 0.8 cm in height (95%CI: -0.16, -0.02), 0.05 cm (95%CI: -0.08, - 0.01) in head circumference, and 0.3 (95%CI: -0.04, -0.02) in Apgar 5 score, except for the chest circumference. Trimester-specific exposure of PM2.5 and PM10 sometimes showed an opposite effect on Additionally, PM2.5 (OR = 1.37, 95%CI: 1.11, 1.68) was correlated with LBW.

Conclusion

Findings in this study suggest a combined impact of fine particulate matter exposure on neonatal development, which adds to the current understanding of PTB risk and health.

Maternal exposure to particulate matter early in pregnancy and congenital anomalies in offspring: Analysis of concentration-response relationships in a population-based cohort with follow-up throughout childhood

Studies have suggested an association between particulate matter (PM) air pollution and certain congenital anomalies (CAs). However, most studies assumed a linear concentration-response relation and were based on anomalies that were ascertained at birth or up to 1 year of age. We investigated associations between exposures to PM during the first trimester of pregnancy and CAs in 9 organ systems using birth and childhood follow-up data from a leading health care provider in Israel. We conducted a retrospective population-based cohort study among 396,334 births, 2004-2015. Daily PM data at a 1 × 1 km spatial grid were obtained from a satellite-derived prediction models and were linked to the mothers' residential addresses at birth. Adjusted odds ratios (ORs) were estimated with logistic regression models using exposure levels as either continuous or categorical variables. We captured 57,638 isolated CAs with estimated prevalence of 96 and 136 anomalies per 1000 births in the first year of life and by age 6 years, respectively. Analysis of continuous PM with diameter < 2.5 μm (PM_2.5) indicated a supra-linear relation with anomalies in the circulatory, respiratory, digestive, genital and integument systems (79 % of CAs). The slope of the concentration-response function was positive and steepest for PM_2.5 lower than the median concentration (21.5 μg/m³) and had a less steep or negative slope at higher levels. Similar trends were observed for PM_2.5 quartiles. For example, for cardiac anomalies, the ORs were 1.09 (95 % confidence interval: 1.02, 1.15), 1.04 (0.98, 1.10) and 1.00 (0.94, 1.07) for births in the second, third and fourth quartiles, respectively, when compared to the first quartile. In sum, this study adds new evidence for adverse effects of air pollution on neonatal health even with low-level air pollution. Information on late diagnosis of children with anomalies is important in evaluating the burden of disease.

The final 28 Days:Prenatal exposure to air pollution and child anthropometric outcomes

This study examines the health consequences of prenatal exposure to air pollution by combining child health data from an original survey with the Air Pollution Index (API) from official Chinese statistics. Our results show that exposure to air pollution in late trimester (four-week windows before delivery) is negatively associated with health outcomes in children in the short and long terms. One standard deviation increase in the API in the final 28 days before delivery decreased birth weight and length by 0.388 and 0.458, respectively, in z-scores and lowered the weight-for-age and height-for-age by 0.370 and 0.441, respectively, in z-scores at 13-15 years post-exposure. Although the timing of exposure and its consequences have been the subject of debate in existing literature, our results focus on four-week windows and demonstrate that exposure during the late pregnancy period may have adverse health effects on children. We conducted analyses that accounted for potential covariates and omitted variables, and our results remain robust and statistically significant. We also found gender heterogeneous effects that girls are more vulnerable to fetal air pollution exposure than boys. Our findings uncover fetal and child health risks regarding air pollution and reinforce the importance of policies for mitigating air pollution in developing countries.

Impact assessment of a raw coal ban on maternal and child health outcomes in Ulaanbaatar: a protocol for an interrupted time series study

INTRODUCTION

Despite a decade of policy actions, Ulaanbaatar's residents continue to be exposed to extreme levels of air pollution, a major public health concern, especially for vulnerable populations such as pregnant women and children. In May 2019, the Mongolian government implemented a raw coal ban (RCB), prohibiting distribution and use of raw coal in households and small businesses in Ulaanbaatar. Here, we present the protocol for an interrupted time series (ITS; a strong quasi-experimental study design for public health interventions) that aims to assess the effectiveness of this coal ban policy on environmental (air quality) and health (maternal and child) outcomes.

METHODS AND ANALYSIS

Routinely collected data on pregnancy and child respiratory health outcomes between 2016 and 2022 in Ulaanbaatar will be collected retrospectively from the four main hospitals providing maternal and/or paediatric care as well as the National Statistics Office. Hospital admissions data for childhood diarrhoea, an unrelated outcome to air pollution exposure, will be collected to control for unknown or unmeasured coinciding events. Retrospective air pollution data will be collected from the district weather stations and the US Embassy. An ITS analysis will be conducted to determine the RCB intervention impact on these outcomes. Prior to the ITS, we have proposed an impact model based on a framework of five key factors, which were identified through literature search and qualitative research to potentially influence the intervention impact assessment.

ETHICS AND DISSEMINATION

Ethical approval has been obtained via the Ministry of Health, Mongolia (No.445) and University of Birmingham (ERN_21-1403). To inform relevant stakeholders of our findings, key results will be disseminated on both (inter)national and population levels through publications, scientific conferences and community briefings. These findings are aimed to provide evidence for decision-making in coal pollution mitigation strategies in Mongolia and similar settings throughout the world.

Sulfur dioxide reduction at coal-fired power plants in North Carolina and associations with preterm birth among surrounding residents

Coal-fired power plants (CFPP) are major contributors of air pollution, including the majority of anthropogenic sulfur dioxide (SO2) emissions, which have been associated with preterm birth (PTB). To address a 2002 North Carolina (NC) policy, 14 of the largest NC CFPPs either installed desulfurization equipment (scrubbers) or retired coal units, resulting in substantial reductions of SO2 air emissions. We investigated whether SO2 air emission reduction strategies at CFPPs in NC were associated with changes in prevalence of PTB in nearby communities.

Methods

We used US EPA Air Markets Program Data to track SO2 emissions and determine the implementation dates of intervention at CFPPs and geocoded 2003-2015 NC singleton live births. We conducted a difference-in-difference analysis to estimate change in PTB associated with change in SO2 reduction strategies for populations living 0-<4 and 4-<10 miles from CFPPs pre- and postintervention, with a comparison of those living 10-<15 miles from CFPPs.

Results

With the spatial-temporal exposure restrictions applied, 42,231 and 41,218 births were within 15 miles of CFPP-scrubbers and CFPP-retired groups, respectively. For residents within 4-<10 miles from a CFPP, we estimated that the absolute prevalence of PTB decreased by -1.5% [95% confidence interval (CI): -2.6, -0.4] associated with scrubber installation and -0.5% (95% CI: -1.6, 0.6) associated with the retirement of coal units at CFPPs. Our findings were imprecise and generally null-to-positive among those living within 0-<4 miles regardless of the intervention type.

Conclusions

Results suggest a reduction of PTB among residents 4-<10 miles of the CFPPs that installed scrubbers.

Ambient air pollutants in the first trimester of pregnancy and birth defects: an observational study

OBJECTIVES

As current studies on the relationships between air pollutants exposure during the first trimester and birth defects were not fully elucidated, this study aimed to assess the association between selected air pollutants and birth defects.

DESIGN

An observational study.

PARTICIPANTS

We obtained 70 854 singletons with gestational age <20 weeks who were delivered at a large maternal and child healthcare centre in Wuhan, China.

OUTCOME MEASURES

Birth defects data and daily average concentration of ambient particulate matter ≤10 µm diameter (PM₁₀), PM ≤2.5 µm diameter (PM_2.5), sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) were obtained. Logistic regression analysis was applied to assess the association between maternal air pollutants exposure during first trimester and total birth defects, congenital heart defects (CHDs), limb defects and orofacial clefts with adjustments of potential covariates.

RESULTS

There were a total of 1352 birth defect cases included in this study, with a prevalence of 19.08‰. Maternal exposed to high concentrations of PM₁₀, PM_2.5, NO₂ and SO₂ in the first trimester were significantly associated with elevated ORs of birth defects (ORs ranged from 1.13 to 1.23). Additionally, for male fetuses, maternal exposed to high PM_2.5 concentration was associated with an elevated odd of CHDs (OR 1.27, 95% CI 1.06 to 1.52). In the cold season, the ORs of birth defects were significantly increased among women exposed to PM_2.5 (OR 1.64, 95% CI 1.41 to 1.91), NO₂ (OR 1.22, 95% CI 1.08 to 1.38) and SO₂ (OR 1.26, 95% CI 1.07 to 1.47).

CONCLUSIONS

This study showed unfavourable effects of air pollutants exposure during the first trimester on birth defects. Especially, the association between maternal PM_2.5 exposure and CHDs was only observed among male fetuses, and stronger effects of PM_2.5, NO₂ and SO₂ exposure on birth defects were observed in the cold season.

Estimating perinatal critical windows of susceptibility to environmental mixtures via structured Bayesian regression tree pairs

Maternal exposure to environmental chemicals during pregnancy can alter birth and children's health outcomes. Research seeks to identify critical windows, time periods when exposures can change future health outcomes, and estimate the exposure-response relationship. Existing statistical approaches focus on estimation of the association between maternal exposure to a single environmental chemical observed at high temporal resolution (e.g., weekly throughout pregnancy) and children's health outcomes. Extending to multiple chemicals observed at high temporal resolution poses a dimensionality problem and statistical methods are lacking. We propose a regression tree-based model for mixtures of exposures observed at high temporal resolution. The proposed approach uses an additive ensemble of tree pairs that defines structured main effects and interactions between time-resolved predictors and performs variable selection to select out of the model predictors not correlated with the outcome. In simulation, we show that the tree-based approach performs better than existing methods for a single exposure and can accurately estimate critical windows in the exposure-response relation for mixtures. We apply our method to estimate the relationship between five exposures measured weekly throughout pregnancy and birth weight in a Denver, Colorado, birth cohort. We identified critical windows during which fine particulate matter, sulfur dioxide, and temperature are negatively associated with birth weight and an interaction between fine particulate matter and temperature. Software is made available in the R package dlmtree.

Early-life exposure to Saharan dust storms and adolescence functional disability: Evidence from Cameroon

The direct link between early-life dust storm exposure and later-in-life outcomes is not fully understood. This study examines the association of functional disability in a large sample of adolescent Cameroonians (N = 112,855) with in-utero and early childhood exposure to Saharan dust storms. Adjusting all estimations for temperature, precipitation, time and location fixed-effects, and person and family sociodemographic characteristics, we documented adverse effects on functional disability in female adolescents due to exposure to dense dust storms during the third gestation trimester and the second postnatal trimester. We also found suggestive evidence that an effect exists for the first as well as the third through fifth postnatal trimesters. In the third trimester of gestation and the second postnatal trimester, exposure to an average length dust storm with PM₁₀ levels beyond 190 μg/m³ increased the likelihood of disability among female adolescents by approximately 229 (95 % CI: 10-464) in 100,000. The size of the adverse effects for the other periods followed similar patterns. These results show the value of creating infrastructures to mitigate or adapt to the effects of dust storms. These endeavors should focus on communities and populations in and around the Sahara where international organizations can play a role. In addition, establishing health data infrastructures not only improves public health but also advances our understanding of the long-term effects of dust storms. This study demonstrates the importance of research on the long-term effects of early-life exposure to dust storms and the need for additional work on this topic.

Air Pollution and Birth Outcomes: Health Impact and Economic Value Assessment in Spain

Air pollution is considered an ongoing major public health and environmental issue around the globe, affecting the most vulnerable, such as pregnant women and fetuses. The aim of this study is to estimate the health impact and economic value on birth outcomes, such as low birthweight (LBW), preterm birth (PTB), small for gestational age (SGA), attributable to a reduction of PM₁₀ levels in Spain. Reduction based on four scenarios was implemented: fulfillment of WHO guidelines and EU limits, and an attributable reduction of 15% and 50% in annual PM₁₀ levels. Retrospective study on 288,229 live-born singleton children born between 2009-2010, using data from Spain Birth Registry Statistics database, as well as mean PM₁₀ mass concentrations. Our finding showed that a decrease in annual exposure to PM₁₀ appears to be associated with a decrease in the annual cases of LBW, SGA and PTB, as well as a reduction in hospital cost attributed to been born with LBW. Improving pregnancy outcomes by reducing the number of LBW up to 5% per year, will result in an estimate associated monetary saving of 50,000 to 7,000,000 euros annually. This study agrees with previous literature and highlights the need to implement, and ensure compliance with, stricter policies that regulate the maximum exposure to outdoor PM permitted in Spain, contributing to decreased environmental health risk, especially negative birth outcomes.

Risks of preterm birth and low birth weight and maternal exposure to NO2/PM2.5 acquired by dichotomous evaluation: a systematic review and meta-analysis

No consistent results from past studies have been found on the relationship between the effects of air pollutant exposure, preterm birth (PTB) and low birth weight (LBW) in fetuses. This study aimed to analyze the impact of high concentrations of air pollutants on the health outcomes of fetuses, especially regarding PTB and LBW. This study used keywords related to air pollutants, pregnancy, and birth outcomes, to search the literature within the databases of the Cochrane Library, PubMed, and Embase, which were published as of July 26, 2022. A total of 24 studies were included in this meta-analysis. This meta-analysis revealed that nitrogen dioxide (NO₂) exposure throughout pregnancy was associated with an increased risk of PTB. Maternal exposure to PM_2.5 (particulate matter sized less than 2.5 μm) during gestation was associated with the risk of LBW. The findings of this meta-analysis provide an important foundation for evaluating the relationship between exposure of air pollutants and fetal birth outcomes in countries with severe air pollution in the future.

Genetic damage and potential mechanism exploration under different air pollution patterns by multi-omics

Ambient air pollution was classified as carcinogenic to humans (Group 1) for lung cancer. DNA damage was an important first step in the process of carcinogenesis, and could also be induced by air pollution. In this study, intratracheal instillation and real-time air exposure system were combined to establish SHP (short-term high-level PM_2.5) and LLPO (long-term low-level PM_2.5 and O₃) exposure patterns, respectively. Hierarchical levels of genetic biomarkers were analyzed to explore DNA damage effects in rats. Representative DNA repair genes from different repair pathways were selected to explore the relative expression levels. The methylation level of differentially expressed repair genes were also determined. Besides, miRNA sequencing and non-targeted metabolomic analysis were performed in rat lungs. KEGG and multi-omics analysis were used to explore the potential mechanism of genetic damage under different air pollution patterns. We found that LLPO exposure induced DSBs and chromosome damage. SHP exposure could induce DSBs and DNA oxidative damage, and the effects of genetic damage under this pollution pattern could be repaired by natural repair. Repair genes involved in two pattern were different. SHP exposure could induce higher methylation levels of RAD51, which might be a potential epigenetic mechanism for high-level PM_2.5 induced down-regulated expression of RAD51 and DSBs. Besides, 29 overlapped alterations in metabolic pathways were identified by metabolomic and miRNA sequencing, including purine metabolism and pyrimidine metabolism after LLPO exposure. Differential miRNAs expression in lung tissue were associated with apoptosis, DNA damage and damage repair. We concluded that under different air pollution patterns, DNA damage biomarkers and activated targets of DNA damage repair network were both different. The genetic damage effects caused by high-level short-term PM_2.5 can be alleviated by natural repair. We provided possible mechanisms by multi-omics which could explain the increased carcinogenic risk caused by air pollution.

Climate change impacts on the health of South Asian children and women subpopulations - A scoping review

Background and objectives

Climate change impacts are felt unequally worldwide; populations that experience geographical vulnerability, those living in small island states and densely populated coastal areas, and children and women are affected disproportionately. This scoping review aims to synthesize evidence from relevant studies centred on South Asia, identify research gaps specifically focused on children and women's health, and contribute to knowledge about South Asia's existing mitigation and adaptation strategies.

Methods

A research librarian executed the search on six databases using controlled vocabulary (e.g., MeSH, Emtree, etc.) and keywords representing the concepts “vulnerable populations” and “climate change” and “health impacts” and “South Asia.” Databases were searched from January 2010 to May 2020. Papers were screened independently by two researchers.

Results

Forty-two studies were included, of which 23 were based in India, 14 in Bangladesh, and five in other South Asian countries. Nineteen studies focused on meteorological factors as the primary exposure. In contrast, thirteen focused on extreme weather events, nine on air pollution, and one on salinity in coastal areas. Thirty-four studies focused on the health impacts on children related to extreme weather events, meteorological factors, and air pollution, while only eight studies looked at health impacts on women. Undernutrition, ARI (acute respiratory infection), diarrheal diseases, low birth weight, and premature mortality were the major health impacts attributed to extreme weather events, meteorological factors, and air pollution exposure in children and women in the region.

Conclusion

Extreme weather events, meteorological factors and air pollution have affected the health of children and women in South Asia. However, the gap in the literature across the South Asian countries concerning relationships between exposure to extreme weather events, meteorological factors, air pollution and health effects, including mental health problems in children and women, are opportunities for future work.

Perinatal Health Inequalities in the Industrial Region of Estonia: A Birth Registry-Based Study

Despite the increasing number of studies on industrially contaminated sites (ICS) and their health effects, there are very few studies on perinatal health outcomes in ICSs. In the present study, we examined the perinatal health inequalities by comparing adverse birth outcomes (ABOs) in the oil shale industry region of Ida-Viru County in Estonia with national-level figures and investigated the effects of maternal environmental and sociodemographic factors. Based on the 208,313 birth records from 2004-2018, Ida-Viru ICS has a birth weight 124.5 g lower than the average of 3544 g in Estonia. A higher prevalence of preterm birth (4.3%) and low birth weight (4.8%) in Ida-Viru ICS is found compared to 3.3% on both indicators at the national level. Multiple logistic regression analysis shows the statistically significant association of ABOs with fine particle (PM_2.5) air pollution, mother's ethnicity, and education throughout Estonia. However, in Ida-Viru ICS, the ABOs odds are remarkably higher in these characteristics except for the mother's ethnicity. Furthermore, the ABOs are associated with the residential proximity to ICS. Thus, the Ida-Viru ICS has unequally higher odds of adverse perinatal health across the environmental and sociodemographic factors. In addition to reducing the air pollutants, policy actions on social disparities are vital to address the country's unjustly higher perinatal health inequalities, especially in the Ida-Viru ICS.

Long-term characterization of roadside air pollutants in urban Beijing and associated public health implications

Road traffic constitutes a major source of air pollutants in urban Beijing, which are responsible for substantial premature mortality. A series of policies and regulations has led to appreciable traffic emission reductions in recent decades. To shed light on long-term (2014-2020) roadside air pollution and assess the efficacy of traffic control measures and their effects on public health, this study quantitatively evaluated changes in the concentrations of six key air pollutants (PM_2.5, PM₁₀, NO₂, SO₂, CO and O₃) measured at 5 roadside and 12 urban background monitoring stations in Beijing. We found that the annual mean concentrations of these air pollutants were remarkably reduced by 47%-71% from 2014 to 2020, while the concurrent ozone concentration increased by 17.4%. In addition, we observed reductions in the roadside increments in PM_2.5, NO₂, SO₂ and CO of 54.8%, 29.8%, 20.6%, and 59.1%, respectively, indicating the high effectiveness of new vehicle standard (China V and VI) implementation in Beijing. The premature deaths due to traffic emissions were estimated to be 8379 and 1908 cases in 2014 and 2020, respectively. The impact of NO₂ from road traffic relative to PM_2.5 on premature mortality was comparable to that of traffic-related PM_2.5 emissions. The public health effect of SO₂ originating from traffic was markedly lower than that of PM_2.5. The results indicated that a reduction in traffic-related NO₂ could likely yield the greatest benefits for public health.

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 (PM_2.5, 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 PM_2.5, 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.

Prenatal exposure to ambient air pollution and adverse birth outcomes: An umbrella review of 36 systematic reviews and meta-analyses

Multiple systematic reviews and meta-analyses linked prenatal exposure to ambient air pollutants to adverse birth outcomes with mixed findings, including results indicating positive, negative, and null associations across the pregnancy periods. The objective of this study was to systematically summarise systematic reviews and meta-analyses on air pollutants and birth outcomes to assess the overall epidemiological evidence. Systematic reviews with/without meta-analyses on the association between air pollutants (NO₂, CO, O₃, SO₂, PM_2.5, and PM₁₀) and birth outcomes (preterm birth; stillbirth; spontaneous abortion; birth weight; low birth weight, LBW; small-for-gestational-age) up to March 30, 2022 were included. We searched PubMed, CINAHL, Scopus, Medline, Embase, and the Web of Science Core Collection, systematic reviews repositories, grey literature databases, internet search engines, and references of included studies. The consistency in the directions of the effect estimates was classified as more consistent positive or negative, less consistent positive or negative, unclear, and consistently null. Next, the confidence in the direction was rated as either convincing, probable, limited-suggestive, or limited non-conclusive evidence. Final synthesis included 36 systematic reviews (21 with and 15 without meta-analyses) that contained 295 distinct primary studies. PM_2.5 showed more consistent positive associations than other pollutants. The positive exposure-outcome associations based on the entire pregnancy period were more consistent than trimester-specific exposure averages. For whole pregnancy exposure, a more consistent positive association was found for PM_2.5 and birth weight reductions, particulate matter and spontaneous abortion, and SO₂ and LBW. Other exposure-outcome associations mostly showed less consistent positive associations and few unclear directions of associations. Almost all associations showed probable evidence. The available evidence indicates plausible causal effects of criteria air pollutants on birth outcomes. To strengthen the evidence, more high-quality studies are required, particularly from understudied settings, such as low-and-middle-income countries. However, the current evidence may warrant the adoption of the precautionary principle.

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

BACKGROUND

A growing body of literature reports associations between exposure to particulate matter with diameter ≤2.5 μm (PM_2.5) during pregnancy and birth outcomes. However, findings are inconsistent across studies.

OBJECTIVES

To assess the association between PM_2.5 and birth outcomes of fetal growth in a cohort with high prevalence of siblings by multilevel models accounting for geographical- and mother-level correlations.

METHODS

In 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 PM_2.5 predictions from a satellite-based spatiotemporal model were linked to the date of birth and maternal residence. We generated mean PM_2.5 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.

RESULTS

In fully adjusted models with a mother-level random intercept only, a 10-μg/m³ increase in PM_2.5 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.

CONCLUSIONS

Consideration of mother-level variability in a region with high fertility rates provides new insights on the strength of associations between PM_2.5 and birth outcomes.

Same environment, stratified impacts? Air pollution, extreme temperatures, and birth weight in South China

This paper investigates whether associations between birth weights and prenatal ambient environmental conditions-pollution and extreme temperatures-differ by 1) maternal education; 2) children's innate health; and 3) interactions between these two. We link birth records from Guangzhou, China, during a period of high pollution, to ambient air pollution (PM₁₀ and a composite measure) and extreme temperature data. We first use mean regressions to test whether, overall, maternal education is an "effect modifier" in the relationships between ambient air pollution, extreme temperature, and birth weight. We then use conditional quantile regressions to test for effect heterogeneity according to the unobserved innate vulnerability of babies after conditioning on other confounders. Results show that 1) the negative association between ambient exposures and birth weight is twice as large at lower conditional quantiles of birth weights as at the median; 2) the protection associated with college-educated mothers with respect to pollution and extreme heat is heterogeneous and potentially substantial: between 0.02 and 0.34 standard deviations of birth weights, depending on the conditional quantiles; 3) this protection is amplified under more extreme ambient conditions and for infants with greater unobserved innate vulnerabilities.

UPLC-Orbitrap-MS/MS Combined With Biochemical Analysis to Determine the Growth and Development of Mothers and Fetuses in Different Gestation Periods on Tibetan Sow Model

Pregnancy is a complex and dynamic process, the physiological and metabolite changes of the mother are affected by different pregnancy stages, but little information is available about their changes and potential mechanisms during pregnancy, especially in blood and amniotic fluid. Here, the maternal metabolism rules at different pregnancy stages were investigated by using a Tibetan sow model to analyze the physiological hormones and nutrient metabolism characteristics of maternal serum and amniotic fluid as well as their correlations with each other. Our results showed that amniotic fluid had a decrease (P < 0.05) in the concentrations of glucose, insulin and hepatocyte growth factor as pregnancy progressed, while maternal serum exhibited the highest concentrations of glucose and insulin at 75 days of gestation (P < 0.05), and a significant positive correlation (P < 0.05) between insulin and citric acid. Additionally, T4 and cortisol had the highest levels during late gestation (P < 0.05). Furthermore, metabolomics analysis revealed significant enrichment in the citrate cycle pathway and the phenylalanine/tyrosine/tryptophan biosynthesis pathway (P < 0.05) with the progress of gestation. This study clarified the adaptive changes of glucose, insulin and citric acid in Tibetan sows during pregnancy as well as the influence of aromatic amino acids, hepatocyte growth factor, cortisol and other physiological indicators on fetal growth and development, providing new clues for the normal development of the mother and the fetus, which may become a promising target for improving the well-being of pregnancy.

The Effect of Nursing Intervention Model Using Mobile Nursing System on Pregnancy Outcome of Pregnant Women

Due to the recent advancement in technology specifically mobile phones, these devices can be used in the hospital to monitor or speed up various activities, which are related to doctors and nurses. In literature, various mechanisms have been presented to resolve this issue, but none of these approaches have considered effectiveness of this technology in the development of a proper mobile nursing system, which is specifically designed for pregnant women. Therefore, in this paper, we have explored the effect of the intervention model based on the mobile nursing system on the pregnancy outcome of pregnant women. In this study, an Android-based mobile nursing monitoring system was adopted to monitor and transmit the human physiological data through physiological parameter monitoring equipment and continuously monitor the physiological parameter data of pregnant women. If the physiological health data of the pregnant woman was abnormal, it had to implement timely nursing intervention. In this study, 266 pregnant women in the electronic records (E-records) were selected as the research objects and divided into two groups according to the intervention method. Pregnant women in group A received routine physical examination during pregnancy, while those in group B received nursing intervention based on mobile nursing system. The results showed that the incidence of each indicator of pregnancy outcome in group B was significantly lower than that in group A, and the difference was statistically significant (P < 0.05). The nursing intervention model based on the mobile nursing system can effectively improve the pregnancy outcome. The mobile nursing system can help nursing staff find the abnormalities of pregnant women during pregnancy and give effective nursing measures in time, which helped improve the pregnancy outcomes, reduce the probability of adverse pregnancy outcomes, ensure the safety of puerperae and newborns, and lessen the delivery risk factors.

The Changing Climate and Pregnancy Health

Purpose of Review

Climate change is the biggest public health threat of the twenty-first century but its impact on the perinatal period has only recently received attention. This review summarizes recent literature regarding the impacts of climate change and related environmental disasters on pregnancy health and provides recommendations to inform future adaptation and mitigation efforts.

Recent Findings

Accumulating evidence suggests that the changing climate affects pregnancy health directly via discrete environmental disasters (i.e., wildfire, extreme heat, hurricane, flood, and drought), and indirectly through changes in the natural and social environment. Although studies vary greatly in design, analytic methods, and assessment strategies, they generally converge to suggest that climate-related disasters are associated with increased risk of gestational complication, pregnancy loss, restricted fetal growth, low birthweight, preterm birth, and selected delivery/newborn complications. Window(s) of exposure with the highest sensitivity are not clear, but both acute and chronic exposures appear important. Furthermore, socioeconomically disadvantaged populations may be more vulnerable.

Summary

Policy, clinical, and research strategies for adaptation and mitigation should be continued, strengthened, and expanded with cross-disciplinary efforts. Top priorities should include (a) reinforcing and expanding policies to further reduce emission, (b) increasing awareness and education resources for healthcare providers and the public, (c) facilitating access to quality population-based data in low-resource areas, and (d) research efforts to better understand mechanisms of effects, identify susceptible populations and windows of exposure, explore interactive impacts of multiple exposures, and develop novel methods to better quantify pregnancy health impacts.

NRF2-Dependent Placental Effects Vary by Sex and Dose following Gestational Exposure to Ultrafine Particles

Exposure to ultrafine particles (UFPs, PM0.1) during pregnancy triggers placental oxidative stress and inflammation, similar to fine PM (PM2.5). The Nrf2 gene encodes a redox-sensitive transcription factor that is a major regulator of antioxidant and anti-inflammatory responses. Disruption of NRF2 is known to substantially enhance PM2.5-driven oxidant and inflammatory responses; however, specific responses to UFP exposure, especially during critical windows of susceptibility such as pregnancy, are not fully characterized; To investigate the role of NRF2 in regulating maternal antioxidant defenses and placental responses to UFP exposure, wildtype (WT) and Nrf2-/- pregnant mice were exposed to either low dose (LD, 100 µg/m3) or high dose (HD, 500 µg/m3) UFP mixture or filtered air (FA, control) throughout gestation; Nrf2-/- HD-exposed female offspring exhibited significantly reduced fetal and placental weights. Placental morphology changes appeared most pronounced in Nrf2-/- LD-exposed offspring of both sexes. Glutathione (GSH) redox analysis revealed significant increases in the GSH/GSSG ratio (reduced/oxidized) in WT female placental tissue exposed to HD in comparison with Nrf2-/- HD-exposed mice. The expression of inflammatory cytokine genes (Il1β, Tnfα) was significantly increased in Nrf2-/- placentas from male and female offspring across all exposure groups. Genes related to bile acid metabolism and transport were differentially altered in Nrf2-/- mice across sex and exposure groups. Notably, the group with the most marked phenotypic effects (Nrf2-/- HD-exposed females) corresponded to significantly higher placental Apoa1 and Apob expression suggesting a link between placental lipid transport and NRF2 in response to high dose UFP exposure; Disruption of NRF2 exacerbates adverse developmental outcomes in response to high dose UFP exposure in female offspring. Morphological effects in placenta from male and female offspring exposed to low dose UFPs also signify the importance of NRF2 in maternal-fetal response to UFPs.

Family Income and Low Birth Weight in Term Infants: a Nationwide Study in Israel

OBJECTIVES

To explore the influence of income on Low Birth Weight (LBW), taking into account other socio-economic measurements.

METHODS

This retrospective cohort study is based on the Israel National Insurance Institute (NII) database. The study population included 58,454 women who gave birth between 2008 and 2013 to 85,605 infants. Only singleton births at term (gestational age in weeks = 37 and later) were included. Logistic regression models with a Generalized Estimating Equation approach were used in order to assess the independent effect of income and Socio-Economic Regional Index (SERI), maternal age, family status, population group and occupational status on LBW. In addition, sibling analysis was conducted to assess the influence of a change in income on birth weight (BW) among 21,998 women.

RESULTS

Lower income was associated with higher odds of LBW (odds ratio (OR) = 1.266; 95% CI:1.115-1.437. Immigrants from Ethiopia, Bedouins from the Negev, the youngest, the oldest, and single mothers had higher odds for LBW newborns. Compared to women whose income quartile had not changed between the most recent and the first births, for women who experienced a deterioration of three and two quartiles in family income, significantly lower birth weight was observed at the time point with lower income: 103 g (p = .049) and 71 g (p = .008), respectively. Improvement in income revealed an almost linear increase in birth weight.

CONCLUSIONS FOR PRACTICE

In an effort to prevent LBW associated mortality and diseases, interventions should be focused first of all on women from population groups who are disadvantaged.

The Asian Games, air pollution and birth outcomes in South China: An instrumental variable approach

We estimate the effects of air-pollution exposure on low birthweight, birthweight, and prematurity risk in South China, for all expectant mothers and by maternal age group and child sex. We do so by exploiting exogenous improvement in air quality during the 2010 Guangzhou Asian Games, when strict regulations were mandated to assure better air quality. We use daily air-pollution levels collected from monitoring stations in Guangzhou, the Asian Games host city, and Shenzhen, a nearby control city, between 2009 and 2011. We first show that air quality during the Asian Games significantly improved in Guangzhou, relative to Shenzhen. Next, using birth-certificate data for both cities for 2009-2011 and using expected pregnancy overlap with the Asian Games as an instrumental variable, we study the effects of three pollutants (PM₁₀, SO₂, and NO₂) on birth outcomes. Four main conclusions emerge: 1) air pollutants significantly reduce average birthweight and increase preterm risk; 2) for birthweight, late pregnancy is most sensitive to PM₁₀ exposure, but there is not consistent evidence of a sensitive period for other pollutants and outcomes; 3) for birthweight, babies of mothers who are at least 35 years old show more vulnerability to all three air pollutants; and 4) male babies show more vulnerability than female babies to PM₁₀ and SO₂, but birthweights of female babies are more sensitive than those of male babies to NO₂.

Environmental impact on reproductive health and risk mitigating strategies

PURPOSE OF REVIEW

The purpose of this review is to increase awareness among reproductive health professionals and trainees about the impact of environmental toxicants and climate change on women's health and mitigation strategies at the individual, professional and governmental levels.

RECENT FINDINGS

Global health indicators reveal a meteoric rise of noncommunicable diseases over the past 50 years, which threaten reproductive health directly and indirectly. Evolutionary genetic mutations as contributors are unlikely in this timeframe, and environmental causes have been invoked. Notably, the past 75 years have witnessed marked increases in industrial chemical production, and global warming has rendered a 'climate crisis' with extreme temperatures and compromised food, water, and air quality. There is now strong experimental and epidemiologic evidence for endocrine disrupting chemicals and particulate matter and chemical components of air pollution in the pathophysiology of human reproductive disorders during development and across the lifespan, especially among vulnerable populations.

SUMMARY

Environmental impacts on fertility, pregnancy outcomes, childhood neurodevelopment, and reproductive tract development are significant, not widely appreciated, and may be preventable. In light of the evidence, education and advocating economical mitigations of toxic environmental chemicals and alternative energy strategies are imperatives to assure quality reproductive health for this and future generations.

Association between ambient air pollution and high-risk pregnancy: A 2015-2018 national population-based cohort study in Korea

BACKGROUND

Several studies have indicated that prenatal exposure to ambient air pollution is associated with an increased risk of gestational diabetes mellitus, hypertensive disorder during pregnancy, preterm birth, and stillbirth. However, no previous study has focused on the association between the number of pregnancy complications and exposure to ambient air pollution.

OBJECTIVES

To investigate the association between prenatal exposure to ambient air pollutants and the number of pregnancy complications in high-risk pregnancies.

METHODS

We collected data on gestational diabetes mellitus, hypertensive disorder during pregnancy, preterm birth, and stillbirth from the National Health Information Databases, provided by the Korean National Health Insurance Service.R To assess individual-level exposure to air pollutants, a spatial prediction model and area-averaging approach were used.

RESULTS

From 2015 to 2018, data of 789,595 high-risk pregnancies were analyzed. The ratio of gestational diabetes mellitus in the country was the highest, followed by preterm birth, hypertensive disorder during pregnancy, and stillbirth. Approximately 71.7% of pregnant women (566,143) presented with one pregnancy complication in identical pregnancies, 27.5% (216,714) presented with two, and 0.9% (6738) presented with three or more. Multiple logistic regression models with adjustments for age, residence, and income variables indicated that the risk of having two or more pregnancy complications was positively associated with the exposure to higher levels of PM₁₀ (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.09-1.12) and PM_2.5 (OR, 1.14; 95% CI, 1.12-1.15). The highest quartile presented higher odds of two or more pregnancy complications compared with the lower three quartiles of PM₁₀, PM_2.5, CO, NO₂, and SO₂ exposures (p < 0.001).

CONCLUSION

The results indicate that the risk of pregnancy complications is positively associated with the exposure to the high concentrations of PM₁₀, PM_2.5, CO, NO₂, and SO₂.

SO2 derivatives induce dysfunction in human trophoblasts via inhibiting ROS/IL-6/STAT3 pathway

BACKGROUND

Epidemiological studies have revealed that sulfur dioxides (SO₂) can increase the risk of pregnancy complications such as missed abortion in the first trimester, stillbirth, preterm birth, small for gestational age, gestational diabetes mellitus and preeclampsia, but the mechanisms underlying these findings remains unknown. What is known, however, is that trophoblasts, a type of fetal cell exerting vital immunologic functions to maintain a successful pregnancy, are usually involved in the pathogenic mechanism of pregnancy complications.

OBJECTIVE

To study the effect of SO₂ derivatives (bisulfite and sulfite, 1:3 M/M) on the function of trophoblasts.

METHODS

Swan.71 trophoblast cells were treated with various concentrations of SO₂ derivatives to determine the effect of SO₂ derivatives on cellular viability by CKK8. Flow cytometry was performed to analyze the effect of SO₂ derivatives on apoptosis, cell cycle and intracellular ROS. Wound healing assay and transwell assay were conducted to examine the migration and invasion of Swan.71 cells. Inflammation-related cytokines in the supernatant (IL-1β, IL-6, IL-8, IL-10 and TNF-α) were measured by IMMULITE®1000 Systems (SIEMENS). The expression level of NLRP3, Caspase1, MMP9, MMP2, STAT3, and p-STAT3 were evaluated by Western Blotting.

RESULTS

Exposure to SO₂ derivatives significantly decreased cellular viability, arrested cell cycle at S/G2/M phase and induced cell apoptosis of Swan.71 trophoblasts. In addition, the migration and invasion of Swan.71 cell were significantly inhibited. SO₂ derivatives also significantly increased IL-1β secretion while it is NLRP3/Caspase1 independent. IL-6 secretion was significant inhibited accompanied by decreased STAT3 phosphorylation and expression of MMP2 and MMP9. The intracellular ROS level was significantly suppressed by SO₂ derivatives.

CONCLUSION

SO₂ derivatives exert toxic effects on trophoblasts which results in: suppressing cellular viability and intracellular ROS level, interfering with cell proliferation through arresting cell cycle, inducing cell apoptosis, disturbing inflammation-related cytokines secretion and inhibiting motility. Decreased ROS/IL-6/STAT3 levels play a role in inhibited cell viability, cell cycle arrest, apoptosis and defective motility.

Gestational exposures to outdoor air pollutants in relation to low birth weight: A retrospective observational study

Findings for impacts of outdoor air pollutants on birth outcomes were controversial. We performed a retrospective observational study in 2527 preschoolers of Shanghai, China and investigated associations of duration-averaged concentrations of outdoor sulphur dioxide (SO₂), nitrogen dioxide (NO₂), and particulate matter with an aerodynamic diameter ≤ 10 μm (PM₁₀) in different months and trimesters of gestation, with preterm birth (PB), low birth weight (LBW), term low birth weight (T-LBW), and small for gestational age (SGA). Daily concentrations of outdoor air pollutants were collected in each residence-located district. Parents reported health information. In the multivariate logistic regression analyses, exposures to outdoor NO₂ were consistently associated with the higher odds of LBW and T-LBW. These associations were generally stronger for early months than for later months of the gestation. Adjusted odds ratios generally were larger in multi-pollutant model than in single-pollutant model. Exposure to NO₂ in the first month of the gestation was significantly associated with T-LBW (adjusted OR, 95%CI: 1.91, 1.02-3.58 for increment of interquartile range (18.5 μg/m³); p-value = 0.044) in multi-pollutant model. This association was stronger in girls, renters, and children whose mothers ≥30 years-old, with household dampness-related exposures, and with parental smoking during pregnancy. Our results indicate that exposure to NO₂ during gestation perhaps is a risk factor for LBW and T-LBW, and effects of NO₂ exposures could be greater during early periods than during later periods of gestation.

Association of maternal ozone exposure with term low birth weight and susceptible window identification

BACKGROUND

Ozone pollution keeps deteriorating in the context of climate change. Maternal ozone exposure may be associated with low birth weight (LBW), but the results are still inconsistent. The identification of the critical exposure windows, a specific period of particular susceptibility during pregnancy, remains unresolved. We aimed to evaluate whether ozone exposure was associated with term LBW and further identify the susceptible exposure windows.

METHODS

A retrospective cohort study was conducted in Guangzhou, a megacity in the most populous and economically developed city clusters in China. We included 444,096 singleton live births between January 2015 and July 2017. From 11 fixed stations, we collected daily 1-h maximum and 8-h maximum moving average ozone level (O₃-1 h and O₃-8 h) and calculated exposures for each participant based on their district of residence during pregnancy. We used traditional Logistic regression to estimate the trimester-specific association between ozone exposure and term LBW, and further estimated monthly- and weekly association by distributed lag models (DLMs) with Logistic regression. Odds ratios (ORs) and 95% confidence intervals (CIs) of term LBW were calculated for an interquartile range (IQR) increase in ozone exposure. Stratified analyses and heterogeneity tests were conducted by maternal age and infant sex.

RESULTS

The incidence of term LBW was 1.9%. During the study period, the mean O₃-1 h and O₃-8 h levels were 112.6 µg/m³ and 84.5 µg/m³, respectively. Increased O₃-1 h (IQR: 90 µg/m³) and O₃-8 h (73 µg/m³) exposure during the second trimester were associated with increased risk of term LBW. At a monthly level, the term LBW risk was associated with O₃-1 h exposure during the 4th-6th month and O₃-8 h exposure during the 6th month. By estimating the weekly-specific association, we observed that critical exposure windows were the 15th- 26th gestational weeks for O₃-1 h, and the 20th-26th weeks for O₃-8 h, respectively. Estimated ORs and 95% CIs ranged from 1.012 (1.000, 1.024) to 1.023 (1.007, 1.039). When examined by subgroups, the effects were present among women ≥ 35 years or < 25 years old and those with female babies.

CONCLUSIONS

This study provides compelling evidence that exposure to O₃ was associated with increased risk of term LBW, and gestational weeks 15th- 26th was found to be particularly susceptible. These findings provide a research basis for further mechanism examination, public health interventions, and targeted environmental policy-making.

Ambient Air Pollution, Extreme Temperatures and Birth Outcomes: A Protocol for an Umbrella Review, Systematic Review and Meta-Analysis

Prenatal exposure to ambient air pollution and extreme temperatures are among the major risk factors of adverse birth outcomes and with potential long-term effects during the life course. Although low- and middle-income countries (LMICs) are most vulnerable, there is limited synthesis of evidence in such settings. This document describes a protocol for both an umbrella review (Systematic Review 1) and a focused systematic review and meta-analysis of studies from LMICs (Systematic Review 2). We will search from start date of each database to present, six major academic databases (PubMed, CINAHL, Scopus, MEDLINE/Ovid, EMBASE/Ovid and Web of Science Core Collection), systematic reviews repositories and references of eligible studies. Additional searches in grey literature will also be conducted. Eligibility criteria include studies of pregnant women exposed to ambient air pollutants and/or extreme temperatures during pregnancy with and without adverse birth outcomes. The umbrella review (Systematic Review 1) will include only previous systematic reviews while Systematic Review 2 will include quantitative observational studies in LMICs. Searches will be restricted to English language using comprehensive search terms to consecutively screen the titles, abstracts and full-texts to select eligible studies. Two independent authors will conduct the study screening and selection, risk of bias assessment and data extraction using JBI SUMARI web-based software. Narrative and semi-quantitative syntheses will be employed for the Systematic Review 1. For Systematic Review 2, we will perform meta-analysis with two alternative meta-analytical methods (quality effect and inverse variance heterogeneity) as well as the classic random effect model. If meta-analysis is infeasible, narrative synthesis will be presented. Confidence in cumulative evidence and the strength of the evidence will be assessed. This protocol is registered with PROSPERO (CRD42020200387).

Prenatal Exposure to Specific PM2.5 Chemical Constituents and Preterm Birth in China: A Nationwide Cohort Study

Exposure to fine particulate matter (PM_2.5) during pregnancy has been associated with preterm birth (PTB). However, the existing evidence is inconsistent, and the roles of specific PM_2.5 chemical constituents remain unclear. Based on the China Labor and Delivery Survey, we included birth data from 89 hospitals in 25 provinces in mainland China, and conducted a national multicenter cohort study to examine the associations of PM_2.5 and its chemical constituents with PTB risk in China. We applied satellite-based models to predict prenatal PM_2.5 mass and six main component exposure. Multilevel logistic regression analysis was used to examine the associations, controlling for sociodemographic characteristics, seasonality, and spatial variation. We observe an increased PTB risk with an increase in PM_2.5 mass and the most significant association is found during the third trimester when the adjusted odds ratio (OR) per interquartile range increases in PM_2.5 total mass is 1.12 (95% confidence Interval, CI: 1.05-1.20). Infants conceived by assisted reproductive technology (ART) show greater PTB risk associated with PM_2.5 exposure (OR = 1.33, 95% CI: 1.05-1.69) than those conceived naturally (OR = 1.11, 95% CI: 1.03-1.19). We also find black carbon, sulfate, ammonium and nitrate, often linked to fossil combustion, have comparable or larger estimates of the effect (OR = 1.07-1.14) than PM_2.5. Our findings provide evidence that components mainly from fossil fuel combustion may have a perceptible influence on increased PTB risk associated with PM_2.5 exposure in China. Additionally, compared to natural conception, conception through ART may be more susceptible to PM_2.5 exposure.

Adverse Birth Outcomes Related to NO2 and PM Exposure: European Systematic Review and Meta-Analysis

There is a growing number of international studies on the association between ambient air pollution and adverse pregnancy outcomes, and this systematic review and meta-analysis has been conducted focusing on European countries, to assess the crucial public health issue of this suspected association on this geographical area. A systematic literature search (based on Preferred Reporting Items for Systematic reviews and Meta-Analyses, PRISMA, guidelines) has been performed on all European epidemiological studies published up until 1 April 2020, on the association between maternal exposure during pregnancy to nitrogen dioxide (NO₂) or particular matter (PM) and the risk of adverse birth outcomes, including: low birth weight (LBW) and preterm birth (PTB). Fourteen articles were included in the systematic review and nine of them were included in the meta-analysis. Our meta-analysis was conducted for 2 combinations of NO₂ exposure related to birth weight and PTB. Our systematic review revealed that risk of LBW increases with the increase of air pollution exposure (including PM₁₀, PM_2.5 and NO₂) during the whole pregnancy. Our meta-analysis found that birth weight decreases with NO₂ increase (pooled beta = −13.63, 95% confidence interval (CI) (−28.03, 0.77)) and the risk of PTB increase for 10 µg/m3 increase in NO₂ (pooled odds ratio (OR) = 1.07, 95% CI (0.90, 1.28)). However, the results were not statistically significant. Our finding support the main international results, suggesting that increased air pollution exposure during pregnancy might contribute to adverse birth outcomes, especially LBW. This body of evidence has limitations that impede the formulation of firm conclusions. Further studies, well-focused on European countries, are called to resolve the limitations which could affect the strength of association such as: the exposure assessment, the critical windows of exposure during pregnancy, and the definition of adverse birth outcomes. This analysis of limitations of the current body of research could be used as a baseline for further studies and may serve as basis for reflection for research agenda improvements.

Traffic-related metrics and adverse birth outcomes: A systematic review and meta-analysis

Given the inconsistency of epidemiologic evidence for associations between maternal exposures to traffic-related metrics and adverse birth outcomes, this manuscript aims to provide clarity on this topic. Pooled meta-estimates were calculated using random-effects analyses. Subgroup analyses were conducted by study area, study design, and Newcastle-Ottawa quality score (NOS). Funnel plots and Egger's test were conducted to evaluate the publication bias, and Fail-safe Numbers (Fail-safe N) were measured to evaluate the robustness of models. From the initial 740 studies (last search, July 11, 2019), 26 studies were included in our analysis. The pooled odds ratio for the change in small for gestational age associated with per 500 m decrease in the distance to roads was 1.016 (95% CI: 1.004, 1.029). Subgroup analyses revealed significant positive associations between term low birth weight and traffic density in higher-quality literatures with higher NOS [1.060 (95% CI: 1.002, 1.121)], cohort studies [1.020 (95% CI: 1.006, 1.033)], and studies in North America [1.018 (95% CI: 1.005, 1.131)]. The buffer of traffic density made no difference in the effect size. Traffic density seemed to be a better indicator of traffic pollution than the distance to roads.

Interaction of Air Pollutants and Meteorological Factors on Birth Weight in Shenzhen, China

BACKGROUND

This study aimed to assess if air pollutants and meteorological factors synergistically affect birth outcomes in Shenzhen, China.

METHODS

A total of 1,206,158 singleton live births between 2005 and 2012 were identified from a birth registry database. Daily average measurements of particulate matter ≤10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ambient air temperature (T), and dew point temperature (Td), a marker of humidity, were collected. Multivariable logistic regression models were used to evaluate associations between air pollution and small for gestational age (SGA), and full-term low birth weight (TLBW). We classified births into those conceived in the warm (May-October) and cold seasons (November-April) and then estimated interactions between air pollutants and meteorological factors.

RESULTS

An interquartile range (IQR) increase in PM10 exposure during the first trimester (23.1 µg/m) and NO2 during both the first and second trimesters (15.1 and 13.4 µg/m) was associated with SGA and TLBW risk; odds ratios ranged from 1.01 (95% confidence interval [CI] = 1.00, 1.02) to 1.09 (1.07, 1.12). We observed interactive effects of both air temperature and humidity on PM10 and SGA for newborns conceived in the warm season. Each IQR increase in PM10 (11.1 µg/m) increased SGA risk by 90% (95% CI = 19%, 205%), 29% (23, 34%), 61% (10, 38%), and 26% (21, 32%) when T < 5th percentile, 5th < T < 95th percentile, Td < 5th percentile, and 5th < Td < 95th percentile, respectively.

CONCLUSIONS

Our study found evidence of an interactive effect of air temperature and humidity on the relationship between PM10 exposure and SGA among newborns conceived in the warm season (May-October). Relatively low air temperature or humidity exacerbated the effects of PM10.

Effects of short-term ambient air pollution exposure on HPV infections: A five-year hospital-based study

Human papillomavirus (HPV) infections are common sexually-transmitted diseases among reproductive-aged women with increasing concern. Until now, there are no prior study about the association between HPV infections and ambient air pollution. This study aimed to explore the relationship between short-term exposure to ambient pollutants and daily outpatient visits for HPV infections in China. Data of daily outpatient visits for HPV infections were obtained from January 1, 2014 to December 31, 2018 (1826 days). Over-dispersed Poisson generalized additive models were applied by adjusting weather conditions and day of the week. We identified a total of 39,746 cases for HPV infections. A 10 μg/m³ increase of PM₁₀, PM_2.5, SO₂, and NO₂ or a 0.1 mg/m³ rise of CO in concurrent day (lag 0) concentrations was related to an elevation of 0.822% (95% Cl: 0.282%, 1.36%), 1.05% (95% Cl: 0.280%, 1.81%), 5.72% (95% Cl: 1.79%, 9.65%), 5.02% (95% Cl: 3.45%, 6.60%), and 2.40% (95% Cl: 1.43%, 3.37%) in daily outpatient-visits for HPV infections, respectively. The association was more significant in those women aged 41 or over. As for 10 μg/m³ increase of O₃, a -1.33% (95% Cl: -2.13%, -0.530%) change was observed on the lag 03 and such effects appeared to be more obvious in the aged 18-40 group. Our results provided the first evidence that short-term exposure to ambient pollutants was related to, which may be indirectly, the increased risk of HPV infections while O₃ may act as a "protective" factor.

Association Between Maternal Normal Range HbA1c Values and Adverse Birth Outcomes

CONTEXT

Higher blood glucose level during gestational periods has been consistently associated with increased risk of adverse birth outcomes. Evidence regarding the association between higher glycated hemoglobin A1c (HbA1c) within the normal range and adverse birth outcomes is limited.

OBJECTIVE

We aimed to examine the association between HbA1c within the normal range and the risk of adverse birth outcomes.

DESIGN AND SETTING

The data were abstracted from the Information System of Guangdong Women and Children Hospital, China, from September 2014 to March 2018.

PATIENTS

A total of 5658 pregnant women with normal gestational HbA1c were included in this analysis.

MAIN OUTCOME MEASURES

The adverse birth outcomes include preterm birth, macrosomia, and large for gestational age (LGA).

RESULTS

Among 5658 subjects, the rates of preterm birth, macrosomia, and LGA were 4.6% (261/5658), 3.5% (200/5658), and 5.7% (325/5658), respectively. The results of multivariate logistic regression model showed that each 1% increase in maternal HbA1c was positively associated with increased risks of preterm birth (OR 1.58; 95% CI, 1.08-2.31), macrosomia (OR 1.70; 95% CI, 1.10-2.64), and LGA (OR 1.38; 95% CI, 0.98-1.96). The association between gestational HbA1c and preterm birth was more evident among women with prepregnancy body mass index (BMI) ≤ 24 kg/m2.

CONCLUSIONS

Gestational higher HbA1c level within the normal range is an independent risk factor for preterm birth, macrosomia, and LGA. Intervention for reducing HbAc1 may help to prevent adverse birth outcomes.

Before the beginning: environmental exposures and reproductive and obstetrical outcomes

There is growing consensus that preconception exposure to environmental toxins can adversely affect fertility, pregnancy, and fetal development, which may persist into the neonatal and adult periods and potentially have multigenerational effects. Here we review current data on preconception and prenatal exposure to several chemicals, including heavy metals, endocrine-disrupting chemicals, pesticides, and air pollution, and their associated obstetrical and reproductive health effects. Reproductive endocrinologists and affiliated health care providers have a unique opportunity to counsel patients before they get pregnant to minimize exposure to hazardous chemicals with the goal to improve reproductive outcomes and assure a healthy lifestyle overall. We provide practical tools and some publicly available resources for reproductive health professionals to assess a patient's risks and ways to reduce chemical and air pollution exposures during the critical preconception and prenatal periods.

The Association Between Air Pollution and Low Birth Weight and Preterm Labor in Ahvaz, Iran

PURPOSE

Pregnant women and fetuses are sensitive to air pollution due to physiological changes in pregnancy. The aim of this study was to determine the relationship between exposure to air pollution, low birth weight and preterm labor in Ahvaz.

METHODS

This research was a time-series study. The research sample consisted of all data about low birth weight and preterm labor pregnant women from Imam Khomeini Hospital and Razi Hospital in Ahvaz city. Air pollutant data including O3, NO, NO2, SO2, CO, PM10 and PM2.5 and climate data were collected from the Environmental Protection Agency and the Khuzestan Province during a 10-year period from 2008 to 2018. The generalized additive models (GAMs) with different air pollutant lags up to 6 days were used.

RESULTS

The results of multiple GAM model have shown that there is a direct and significant relationship between exposure to PM10 at 0-6-day lag, SO2 at 2- and 3-day lag and low birth weight. In addition, there was a direct and significant correlation between exposure to NO2, NO, CO and PM2.5 at 0-6-day lag and preterm labor.

CONCLUSION

The results indicate the effect of air pollutants on low birth weight and preterm labor. Therefore, pregnant women should be informed about the negative consequences of air pollution and avoid exposure to polluted air during pregnancy.

Epidemiology of birth defects based on a birth defect surveillance system in Southern Jiangsu, China, 2014-2018

Introduction: Changzhou has been confronted with great challenges in birth defects (BDs) prevention, as the prevalence rates of BDs in Changzhou increased rapidly. The aims of this study were to describe the epidemiology of BDs in perinatal infants (PIs, including dead fetus, stillbirth, or live birth between 28 weeks of gestation and 7 days after birth) in Changzhou during the period from 2014 to 2018.Methods: The BD surveillance data of PIs were collected from 56 hospitals of Changzhou. The prevalence rate of BDs with 95% confidence interval (CI) were calculated by Poisson distribution. Univariate and multivariate Poisson regression was performed to identify the changing trends of prevalence rates of BDs by year and the association of regarding BD characteristics including year, infant gender, maternal age, and season with BDs successively.Results: From 2014 to 2018, there were a total of 238,712 PIs of which 1707 had BDs, with the average prevalence of 71.509 per 10,000 PIs, showing a remarkable uptrend (aPRR = 1.133, 95%CI: 1.094-1.173). The ten leading BDs were polydactyly, congenital heart defects (CHD), syndactyly, microtia, cleft lip and palate (CLP), hypospadias, cleft palate, other malformation of external ear (OMEE), congenital atresia of rectum and anus, and congenital talipes equinovarus (CTE). During the study period, the prevalence rates of polydactyly, CHD and syndactyly increased significantly (PRR = 1.195, 95%CI: 1.109-1.288, PRR = 1.194, 95%CI: 1.105-1.291, and PRR = 1.143, 95%CI: 1.007-1.297, respectively); the prevalence rates of congenital esophageal atresia decreased significantly (PRR = 0.571, 95%CI: 0.395-0.826). The risk of BDs was higher in male PIs versus female PIs (aPRR = 1.235, 95%CI: 1.123-1.358).Conclusions: A significant increase in the prevalence of BDs was detected from 2014 to 2018 in Changzhou. CHD, polydactyly, and syndactyly increased much and congenital esophageal atresia declined much. Male PIs was risk factor for occurrence of BDs. Collecting information on factors associated with BDs, setting the report time of BDs system at smaller gestational age so as to get an exact prevalence and make better prevention strategy, strengthening the publicity and education, improving the ability of monitoring, and wider use of new diagnosis technology are important to reduce the prevalence of BDs in PIs.

Combined effects of ambient air pollution and home environmental factors on low birth weight

BACKGROUND

Low birth weight (LBW) remains a major public health problem worldwide, yet its crucial environmental risk factors are still unclear.

OBJECTIVE

To examine the association between LBW (term and preterm LBW) and prenatal exposure to ambient air pollution and home environmental factors as well as their combination, in order to identify critical time window for exposure and key outdoor and indoor factors in LBW development.

METHODS

A cohort study of 3509 preschool children was performed in Changsha, China during the period 2011-2012. A questionnaire was conducted to survey each child's birth outcome and each mother's exposure to home environmental factors including parental smoking, new furniture, redecoration, mold/damp stains, window pane condensation, and household pets during pregnancy. Maternal exposure to inhalable particulate matter (PM₁₀), industrial air pollutant (SO₂), and traffic air pollutant (NO₂) was estimated during different time windows of gestation, including conception month, three trimesters, birth month, and whole gestation. Associations of term and preterm LBW with ambient air pollutants and home environmental factors were assessed by multiple logistic regression models in terms of odds ratio (OR) with 95% confidence interval (CI).

RESULTS

Term LBW (TLBW) was significantly associated with exposure to ambient PM₁₀ during pregnancy, with OR (95% CI) = 1.47 (1.00-2.14) for per IQR increase after adjustment for the covariates and home environmental factors. Specifically, we identified the significant association in early phase of pregnancy including conception month (1.90, 1.09-3.30) and the first trimester (1.72, 1.10-2.69). We further found that TLBW was significantly related with parental smoking at home, OR (95% CI) = 2.17 (1.09-4.33). However, no association was observed for preterm LBW (PLBW). The TLBW risk of ambient air pollution and home environmental factors was independent each other and hence the combined exposure to ambient PM₁₀ and indoor parental smoking caused the highest risk. Sensitivity analysis suggested that foetus with younger mothers were significantly more susceptible to risk of indoor parental smoking, while those with smaller house and cockroaches were more sensitive to risk of outdoor PM₁₀ exposure.

CONCLUSION

Prenatal exposure to combined outdoor and indoor air pollution, particularly in critical window(s) during early pregnancy, significantly increases the risk of term LBW.