BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) have been linked to adverse birth outcomes that have been reported to be induced by oxidative stress, but few epidemiological studies to date have evaluated associations between urinary PAH metabolites and oxidative stress biomarkers in pregnancy and identified critical periods for these outcomes and PAH exposures in pregnancy.
METHODS: A cohort of pregnant women was recruited early in pregnancy from antenatal clinics at the University of California Los Angeles during 2016-2019. We collected urine samples up to three times during pregnancy in a total of 159 women enrolled in the cohort. A total of 7 PAH metabolites and 2 oxidative stress biomarkers [malondialdehyde (MDA), 8-hydroxy-2\'-deoxyguanosine (8-OHdG)] were measured in all available urine samples. Using multiple linear regression models, we estimated the percentage change (%) and 95% confidence interval (CI) in 8-OHdG and MDA measured at each sample collection time per doubling of PAH metabolite concentrations. Furthermore, we used linear mixed models with a random intercept for participant to estimate the associations between PAH metabolite and oxidative stress biomarker concentrations across multiple time points in pregnancy.
RESULTS: Most PAH metabolites were positively associated with both urinary oxidative stress biomarkers, MDA and 8-OHdG, with stronger associations in early and late pregnancy. A doubling of each urinary PAH metabolite concentration increased MDA concentrations by 5.8-41.1% and 8-OHdG concentrations by 13.8-49.7%. Linear mixed model results were consistent with those from linear regression models for each gestational sampling period.
CONCLUSIONS: Urinary PAH metabolites are associated with increases in oxidative stress biomarkers during pregnancy, especially in early and late pregnancy.

OBJECTIVE: Limited knowledge exists regarding exposures to non-therapeutic chemicals by women planning to conceive, or during pregnancy or breastfeeding. The Swiss Teratogen Information Service (STIS) provides information to healthcare professionals about medications and other exposures during pregnancy or breastfeeding. This study aimed to describe the queries on non-therapeutic chemicals addressed to the STIS over the past two decades.
METHODS: Using data from the STIS for the years 2000 to 2019, we conducted a descriptive analysis of all queries related to women\'s exposures to non-therapeutic chemicals during pregnancy planning, pregnancy or breastfeeding.
RESULTS: Over two decades, the STIS database recorded 320 exposures to chemicals. Workplace settings accounted for over 60% of queries, followed by exposures at home (20%). In almost half (48%) of the queries, more than one chemical was mentioned, totalling 885 chemicals across these 320 queries. Commonly mentioned chemicals included isopropanol, acetone and lead. Solvents were the leading category of products (16%), followed by cleaning products (10%), paints (8%) and insecticides (5%). The follow-up data showed five diverse cases of congenital malformations, accounting for 4.0% (5 out of 125) of the sample, a figure in line with the background risk of malformations in the general population.
CONCLUSIONS: This study emphasises the importance of conducting research that comprehensively captures the highly heterogeneous exposures to non-therapeutic chemicals during pregnancy and suggests that attention should be given not only to professional settings, but also to domestic contexts.

UNASSIGNED: This research aims to analyze how exposure to fine particulate matter (PM2.5) and ambient heat during pregnancy increases the risk of congenital hydronephrosis (CH) in newborns.
UNASSIGNED: A case-control study was conducted to investigate the relationship between exposure to PM2.5 and ambient heat during pregnancy and the occurrence of CH in newborns. The study, which was conducted from 2015 to 2020, included 409 infants with CH as the case group and 409 infants without any abnormalities as the control group. Using spatial remote sensing technology, the exposure of each pregnant mother to PM2.5 concentration was meticulously mapped. Additionally, data on the ambient temperature of exposure for each participant were also collected. A logistics regression model was used to calculate the influence of exposure to PM2.5 and ambient heat on the occurrence of CH. Stratified analysis and interaction analysis were used to study the interaction between ambient heat exposure and PM2.5 on the occurrence of CH.
UNASSIGNED: At the 6th week of gestation, exposure to PM2.5 may increase the risk of CH. For every 10 μg/m3 increase in PM2.5 exposure, the risk of CH increased by 2% (95%CI = 0.98, 1.05) at a p-value of >0.05, indicating that there was no significant relationship between the results. Exposure to intense heat at 6th and 7th weeks of gestation increased the risk of CH. Specifically, for every 1°C increase in heat exposure, the risk of CH in offspring increased by 21% (95%CI = 1.04, 1.41) during the 6th week and 13% during the 7th week (95%CI = 1.02, 1.24). At 5th and 6th weeks of gestation, the relative excess risk due to interaction (RERI) was greater than 0 at the 50th percentile (22.58°C), 75th percentile (27.25°C), and 90th percentile (29.13°C) of daily maximum temperature (Tmax) distribution, indicating that the risk of CH was higher when exposed to both ambient heat and PM2.5 at the same time compared to exposure to a single risk factor.
UNASSIGNED: Exposure to higher levels of PM2.5 and ambient heat during pregnancy increases the risk of CH in infants. There was a positive interaction between exposure to intense heat and high concentration of PM2.5 on the occurrence of CH.

Bisphenol A (BPA) is a phenolic chemical that has been found to be associated with human health outcomes. It is one of the risk factors of thyroid function. Pregnancy is a vulnerable window for thyroid problems, because of the fluctuations in hormone levels. This review aimed to evaluate the association between BPA exposure and thyroid function during pregnancy. We conducted a comprehensive search of relevant databases, including PubMed, Scopus, Embase, Web of Science, and the Cochrane Library, for original studies published in English that reported data on BPA levels and thyroid-related hormone levels in pregnant women. We used the Newcastle-Ottawa Scale (NOS) to assess the methodological quality of the studies and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method to evaluate the quality of evidence. In total, 11 studies involving 6,526 individuals were included in this systematic review. These studies explored fluctuations in thyroid-related hormones, including TSH, TT3, TT4, FT3, and FT4 levels, as well as the TT4/TT3 and FT4/FT3 ratios. The systematic review is to evaluate the evidences between bisphenol A exposure and thyroid-related hormones in pregnant women. We found that BPA exposure in pregnancy might disturb the homeostasis of maternal thyroid-related hormones and suggest the increased risk of hyperthyroidism. Further studies based on the findings are required to explore the underlying mechanisms and determine the potential effects of BPA exposure to thyroid function during pregnancy.

BACKGROUND: Exposure to floods might increase the risks of adverse birth outcomes. However, the current evidence is scarce, inconsistent, and has knowledge gaps. This study aims to estimate the associations of flood exposure before and during pregnancy with adverse birth outcomes and to identify susceptible exposure windows and effect modifiers.
METHODS: In this cohort study, we obtained all the birth records occurring in Greater Sydney, Australia, from Jan 1, 2001, to Dec 31, 2020, from the New South Wales Midwives Data Collection and in the Brisbane metropolitan region, Australia, from Jan 1, 1995, to Dec 31, 2014, from the Queensland Health Perinatal Data Collection. For each birth, residential address and historical flood information from the Dartmouth Flood Observatory were used to estimate the numbers of days with floods during five exposure windows (Pre-1 was defined as 13-24 weeks before the last menstrual period [LMP], Pre-2 was 0-12 weeks before the LMP, trimester 1 [Tri-1] was 0-12 weeks after the LMP, trimester 2 [Tri-2] was 13-28 weeks after the LMP, and trimester 3 [Tri-3] was ≥29 weeks after the LMP). We estimated the hazard ratios (HRs) of adverse birth outcomes (preterm births, stillbirths, term low birthweight [TLBW], and small for gestational age [SGA]) associated with flood exposures in the five exposure windows using Cox proportional hazards regression models.
RESULTS: 1 338 314 birth records were included in our analyses, which included 91 851 (6·9%) preterm births, 9831 (0·7%) stillbirths, 25 567 (1·9%) TLBW, and 108 658 (8·1%) SGA. Flood exposure in Pre-1 was associated with increased risks of TLBW (HR 1·06 [95% CI 1·01-1·12]) and SGA (1·04 [1·01-1·06]); flood exposure during Tri-1 was associated with increased risks of preterm births (1·03 [1·002-1·05]), stillbirth (1·11 [1·03-1·20]), and SGA (1·03 [1·01-1·06]). In contrast, flood exposures during Pre-2 and Tri-3 were associated with reduced risks.
CONCLUSIONS: Exposures to floods in Pre-1 and Tri-1 are both associated with increased risks of adverse birth outcomes, and the risks increase with a higher exposure. Upon planning for conception and prenatal care, individuals and health practitioners should raise awareness of the increased risks of adverse birth outcomes after experiencing floods.
BACKGROUND: The Australian Research Council and the Australian National Health and Medical Research Council.

UNASSIGNED: To investigate the association between exposure to atmospheric pollutants and preterm birth in a river valley-type city and its critical exposure windows.
UNASSIGNED: A retrospective cohort study was used to collect data from the medical records of preterm and full-term deliveries in two hospitals in urban areas of a typical river valley-type city from January 2018 to December 2019. A total of 7,288 cases were included in the study with general information such as pregnancy times, the number of cesarean sections, occupation, season of conception and regularity of the menstrual cycle. And confounding factors affecting preterm birth were inferred using the chi-square test. The effects of exposure to each pollutant, including particulate matter 2.5 (PM2.5), particulate matter 10 (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO) and ozone (O3), during pregnancy on preterm birth and the main exposure windows were explored by establishing a logistic regression model with pollutants introduced as continuous variables.
UNASSIGNED: Maternal age, pregnancy times, number of births, number of cesarean sections, season of conception, complications diseases, comorbidities diseases, hypertension disorder of pregnancy and neonatal low birth weight of the newborn were significantly different between preterm and term pregnant women. Logistic regression analysis after adjusting for the above confounders showed that the risk of preterm birth increases by 0.9, 0.6, 2.4% in T2 and by 1.0, 0.9, 2.5% in T3 for each 10 μg/m3 increase in PM2.5, PM10, NO2 concentrations, respectively. The risk of preterm birth increases by 4.3% in T2 for each 10 μg/m3 increase in SO2 concentrations. The risk of preterm birth increases by 123.5% in T2 and increases by 188.5% in T3 for each 10 mg/m3 increase in CO concentrations.
UNASSIGNED: Maternal exposure to PM2.5, PM10, NO2, CO was associated with increased risk on preterm birth in mid-pregnancy (T2) and late pregnancy (T3), SO2 exposure was associated with increased risk on preterm birth in mid-pregnancy (T2).

UNASSIGNED: Prior research has linked exposure to particulate matter with an aerodynamic diameter of ≤2.5 μm (PM2.5) with preterm birth (PTB). However, the modulating effect of preconception thyroid stimulating hormone (TSH) levels on the relationship between PM2.5 exposure and PTB has not been investigated.
UNASSIGNED: This study aimed to assess whether preconception TSH levels modulate the impact of PM2.5 exposure on PTB.
UNASSIGNED: This cohort study was conducted in Guangdong, China, as a part of the National Free Pre-Pregnancy Checkups Project. PM2.5 exposure was estimated by using the inverse distance weighting method. To investigate the moderating effects of TSH levels on trimester-specific PM2.5 exposure and PTB, we used the Cox proportional hazards model. Additionally, to identify the susceptible exposure windows for weekly specific PM2.5 exposure and PTB, we built distributed lag models incorporating Cox proportional hazards models.
UNASSIGNED: A total of 633,516 women who delivered between January 1, 2014, to December 31, 2019, were included. In total, 34,081 (5.4%) of them had abnormal preconception TSH levels. During the entire pregnancy, each 10-μg/m3 increase in PM2.5 was linked to elevated risks of PTB (hazard ratio [HR] 1.559, 95% CI 1.390-1.748), early PTB (HR 1.559, 95% CI 1.227-1.980), and late PTB (HR 1.571, 95% CI 1.379-1.791) among women with abnormal TSH levels. For women with normal preconception TSH levels, PM2.5 exposure during the entire pregnancy was positively associated with the risk of PTB (HR 1.345, 95% CI 1.307-1.385), early PTB (HR 1.203, 95% CI 1.126-1.285), and late PTB (HR 1.386, 95% CI 1.342-1432). The critical susceptible exposure windows were the 3rd-13th and 28th-35th gestational weeks for women with abnormal preconception TSH levels, compared to the 1st-13th and 21st-35th gestational weeks for those with normal preconception TSH levels.
UNASSIGNED: PM2.5 exposure was linked with a higher PTB risk, particularly in women with abnormal preconception TSH levels. PM2.5 exposure appears to have a greater effect on pregnant women who are in the early or late stages of pregnancy.

UNASSIGNED: We review the prevalence of allergic diseases in children across prenatal exposures to heavy metals.
UNASSIGNED: This systematic review and meta-analysis is registered in the PROSPERO database (CRD42023478471). A comprehensive search of PubMed, Web of Science, Medline and Cochrane library was conducted from the database inception until 31 October 2023. The Newcastle-Ottawa Quality Assessment Scale (NOS) was used to assess the quality of included studies. We used a random-effects model to summarize the effects from the studies.
UNASSIGNED: A total of 16 studies were included, 120,065 mother-child pairs enrolled. The NOS scores indicated that the quality of the literature included in the study was of a high standard.
UNASSIGNED: The final results indicate that prenatal exposure to Pb increased the incidence of wheeze and Eczema in infants, and exposure to Ni and CD increased the incidence of AD in infants.

It remains unclear whether and how maternal exposure to biomass fuel influences infant anthropometry or body proportionality at birth, which are linked to their survival, physical growth, and neurodevelopment. Therefore, this study seeks to explore the association between household-level exposure to biomass cooking fuels and infant size and body proportionality at birth among women in rural Bangladesh. A total of 909 women were derived from the Pregnancy Weight Gain study, which was conducted in Matlab, a rural area of Bangladesh. Infant\'s weight (g), length (cm), head circumference (cm), small for gestational age (SGAW), short for gestational age (SGAL), low head circumference for gestational age (SGAHC), ponderal index, and cephalization index at birth were the outcomes studied. Of the women, 721 (79.3%) were dependent on biomass fuel. Compared to infants born to mothers who used gas for cooking, those born to biomass users had lower weight (β - 94.3, CI - 155.9, - 32.6), length (β - 0.36, 95% CI - 0.68, - 0.04), head circumference (β - 0.24, CI - 0.47, - 0.02) and higher cephalization index (β 0.03, CI 0.01, 0.05) at birth. Maternal biomass exposure is more likely to lead to symmetric SGA, although there is evidence for some brain-sparing effects.

Current scientific knowledge is insufficient on the effects of metal mixtures on early life growth trajectories. This study included 7118 mother-infant pairs from a Chinese birth cohort. Concentrations of 18 maternal urinary metals were quantified, and growth trajectories were conducted based on standardized body mass index (BMI) for up to eight times from 0 to 2 years. A three-phase analytical framework was applied to explore the risk ratios (RR) and 95 % confidence intervals (95 % CI) of co-exposure to metals on dynamic growth, along with potential modifiers. Five growth trajectory groups were identified. Exposure to metal mixtures driven by thallium (Tl, 34.8 %) and aluminum (Al, 16.2 %) was associated with an increased risk of low-rising trajectory (RR=1.58, 95 % CI: 1.25, 2.00); however, exposure to mixtures driven by strontium (Sr, 49.5 %) exhibited an inverse correlation (RR = 0.81, 95 % CI: 0.67, 0.97). Furthermore, infants with varying levels of Tl, Al and Sr, as well as modifiers including pre-pregnancy BMI and infant sex faced distinct risks of low-rising trajectory. Our findings highlighted the Tl, Al, and Sr as key metals in relation to the low-rising trajectory in early life characterized as catch-up growth, with pre-pregnancy BMI and infant sex exerting as potential modifiers.