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

Associations of preconception air pollution exposure with growth trajectory in young children: A prospective cohort study

Gestational air pollution exposure was associated with childhood obesity. However, little is known about the effect of air pollution exposure during the preconception period, a critical window when environmental exposures may affect body growth trajectory and increase obesity risk. We conducted a population-based prospective cohort study of preconception women and their newborn children followed until 2 years old from metropolitan Shanghai, China to investigate the impact of preconception air pollution on childhood weight and body mass index (BMI) growth trajectories. Exposures to PM2.5, PM10, and NO2 during 3 months before conception and each trimester of pregnancy were estimated using high-resolution spatiotemporal models matched at residential addresses. Children's weight and BMI were assessed postnatally every three months. Multivariate and longitudinal models with piecewise linear mixed effects were used to examine the relationship between preconception air pollution and child growth trajectories of weight, BMI, and standardized BMI (BMIZ). The study population comprised 26,714 women in the baseline enrolled in preconception clinics and 5,834 children reached 2 years included in the analysis with 34,398 longitudinal weight and height measurements. One interquartile range (IQR) increase in preconception PM2.5 (16.2 μg/m3) was associated with a 0.078 (95% confidence interval (CI): 0.002-0.154, p = 0.04) increase in attained BMIZ and 1 IQR increase of PM10 (21.1 μg/m3) were associated with an 0.093 (95% CI: 0.002-0.184, p = 0.04) kg/m2 increase in attained BMI, respectively, at the age of two years, after controlling for individual covariates and gestational air pollution exposure. Higher weight, BMI, and BMIZ growth rates during 6-24 months of life were also associated with higher preconception NO2 and PM exposure. Males and children born to mothers less than 35 years old or with overweight/obesity status were more affected by preconception air pollution exposure on weight growth. The 3-month preconception period was a critical time window for air pollution exposure.

Association of air purifier usage during pregnancy with adverse birth outcomes: the Japan Environment and Children's Study

OBJECTIVE

Previous studies have reported that ambient air pollutants such as PM2.5 can increase the risk of adverse birth outcomes. The objective of this study was to ascertain whether air purifier usage during pregnancy is associated with a lower risk of adverse birth outcomes in a large Japanese birth cohort.

METHODS

We conducted a prospective cohort analysis using data from the Japan Environment and Children's Study. Use of air purifiers during pregnancy was assessed using a self-administered questionnaire. Primary outcomes were the prevalence of preterm birth (PTB), small for gestational age (SGA), and low birth weight (LBW). Logistic regression analysis was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The prevalence of outcomes was 4.5% for PTB, 7.4% for SGA, and 8.1% for LBW. The crude model analysis revealed that PTB, SGA, and LBW showed lower ORs in the group that used an air purifier, although the association disappeared in the adjusted model except for SGA (OR: 0.94; 95% CI: 0.89, 1.00, p = 0.048) and LBW (OR: 0.93; 95% CI: 0.88, 0.98, p = 0.003). Subgroup analysis stratified by infant sex revealed that the lower OR for LBW was observed only in male infants.

CONCLUSIONS

Our results suggest that avoiding maternal air pollution exposure during pregnancy may be useful in preventing adverse birth outcomes. These findings provide evidence supporting the development of protective measures against air pollutants in the gestational period by relevant health agencies.

Association Between Sleep Quality and Duration During Pregnancy and Risk of Infant Being Small for Gestational Age: Prospective Birth Cohort Study

BACKGROUND

Maternal sleep disturbance is a risk factor for adverse outcomes like preterm birth. However, the association of maternal sleep quality and duration with the risk of the infant being small for gestational age (SGA) remains inconclusive, and the specific critical window of vulnerability has yet to be clearly identified. Therefore, this study aims to investigate the effect of maternal sleep quality and duration on the risk of having an SGA infant and to identify the critical window for this association.

METHODS

One thousand six hundred and seventy-seven participants from the Shenzhen Birth Cohort Study were included. Maternal sleep duration and quality during pregnancy were assessed using the Pittsburgh Sleep Quality Index (PSQI) in early (<19 weeks), mid- (24-28 weeks), and late (32-38 weeks) pregnancy. Multivariate logistic regression analyses were used to examine the association of an SGA infant with sleep duration and quality, along with their specific effects across the different pregnancy stages.

RESULTS

The pregnant women with short sleep duration (≤7 h/day) in the early stage of pregnancy appeared to have a higher risk of having an SGA infant (aOR = 1.93, 95% CI = 1.32~2.79). Additionally, poor sleep quality combined with short sleep duration was associated with an even higher risk of having an SGA infant (aOR = 2.08, 95% CI = 1.32~3.23). However, this association was observed only during early pregnancy.

CONCLUSIONS

The women with short sleep duration were associated with SGA risk, and the early stage of pregnancy might be a particularly sensitive period for this relationship. Addressing maternal sleep problems during pregnancy as part of antenatal care is crucial for reducing the likelihood of having an SGA infant and improving the overall birth outcomes.

Prenatal exposure to ambient air pollution and risk of fetal overgrowth: Systematic review of cohort studies

OBJECTIVES

Fetal overgrowth has detrimental effects on both the mother and the fetus. The global issue of ambient air pollution has been found to contribute to fetal overgrowth through various pathways. This study aimed to identify the association between prenatal exposure to ambient air pollution and the risk of fetal overgrowth.

METHODS

We identified articles between January 2013 and February 2024 by searching the Web of Sciences(WoS), PubMed, Proquest, Scopus, and Google Scholar databases. Quality assessment was performed using the Newcastle Ottawa scale. This review was provided based on the PRISMA guideline and registered with PROSPERO, "CRD42023488936".

RESULTS

The search generated 1719 studies, of which 22 cohort studies were included involving 3,480,041 participants. Results on the effects of air pollutants on fetal overgrowth are inconsistent because they vary in population and geographic region. But in general, the results indicate that prenatal exposure to air pollutants, specifically PM2.5, NO2, and SO2, is linked to a higher likelihood of fetal overgrowth(macrosomia and large for gestational age). Nevertheless, the relationship between CO and O3 pollution and fetal overgrowth remains uncertain. Furthermore, PM10 has a limited effect on fetal overgrowth. It is essential to consider the time that reproductive-age women are exposed to air pollution. Exposure to air pollutants before conception and throughout pregnancy has a substantial impact on the fetus's vulnerability to overgrowth.

CONCLUSIONS

Fetal overgrowth has implications for the health of both mother and fetus. fetal overgrowth can cause cardiovascular diseases, obesity, type 2 diabetes, and other diseases in adulthood, so it is considered an important issue for the health of the future generation. Contrary to popular belief that air pollution leads to intrauterine growth restriction and low birth weight, this study highlights that one of the adverse consequences of air pollution is macrosomia or LGA during pregnancy. Therefore governments must focus on implementing initiatives that aim to reduce pregnant women's exposure to ambient air pollution to ensure the health of future generations.

Critical windows of greenness exposure during preconception and gestational periods in association with birthweight outcomes

Few studies have examined the association between greenness exposure and birth outcomes. This study aims to identify critical exposure time windows during preconception and pregnancy for the association between greenness exposure and birth weight. A cohort of 13 890 pregnant women and newborns in Shanghai, China from 2016-2019 were included in the study. We assessed greenness exposure using Normalized Difference Vegetation Index (NDVI) during the preconception and gestational periods, and evaluated the association with term birthweight, birthweight z-score, small-for-gestational age, and large-for-gestational age using linear and logistic regressions adjusting for key maternal and newborn covariates. Ambient temperature, relative humidity, ambient levels of fine particles (PM2.5) and nitrogen dioxide (NO2) assessed during the same period were adjusted for as sensitivity analyses. Furthermore, we explored the potential different effects by urbanicity and park accessibility through stratified analysis. We found that higher greenness exposure at the second trimester of pregnancy and averaged exposure during the entire pregnancy were associated with higher birthweight and birthweight Z-score. Specifically, a 0.1 unit increase in second trimester averaged NDVI value was associated with an increase in birthweight of 10.2 g (95% CI: 1.8-18.5 g) and in birthweight Z-score of 0.024 (0.003-0.045). A 0.1 unit increase in an averaged NDVI during the entire pregnancy was associated with 10.1 g (95% CI: 1.0-19.2 g) increase in birthweight and 0.025 (0.001-0.048) increase in birthweight Z-score. Moreover, the associations were larger in effect size among urban residents than suburban residents and among residents without park accessibility within 500 m compared to those with park accessibility within 500 m. Our findings suggest that increased greenness exposure, particularly during the second trimester, may be beneficial to birth weight in a metropolitan area.

Associations between maternal exposure to air pollution during pregnancy and trajectories of infant growth: A birth cohort study

OBJECTIVE

We examined the relationships between infants' growth trajectories and prenatal exposure to air pollution, which is still under-investigated.

METHODS

A birth cohort study was constructed using medical records of pregnant women and infants born between 2015 and 2019 in Foshan, China. Using satellite-based spatial-temporal models, prenatal exposure to air pollutants including particulate matter with an aerodynamic dimension of < 2.5 µm (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) was assessed at each woman's residence. Latent class growth modeling was used to identify trajectories of physical (body length and weight) growth and neurodevelopment, which were repeatedly measured within 1 year after birth. Logistic regression models were used to investigate the associations between prenatal exposure to air pollution and the risks of growth disorders, adjusting for an array of potential confounders.

RESULTS

We identified two growth trajectories for body length [normal: 3829 (93%); retardation: 288 (7%)], three for weight [normal: 2475 (59.6%); retardation: 390 (9.4%); overgrowth: 1287 (31%)], and two for neurodevelopment [normal: 956 (66.1%); retardation: 491 (33.9%)]. For exposure over whole pregnancy, SO2 was associated with an increased risk of body length retardation (OR for per 1 µg/m3 increment: 1.09, 95%CI: 1.01-1.17); PM2.5 (OR: 1.05, 95%CI: 1.03-1.07), SO2 (OR: 1.15, 95%CI: 1.08-1.22), and NO2 (OR: 1.05, 95%CI: 1.03-1.07) were positively associated with neurodevelopmental retardation. Such associations appeared stronger for exposures over the first and second trimesters. No significant associations were detected for weight growth.

CONCLUSIONS

Maternal exposure to air pollution during pregnancy was associated with higher risks of impairments in both physical growth, particularly body length, and neurodevelopment.