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Exposure to chromium is increasing due to environmental pollution from industrial processes. Several epidemiological studies have investigated chromium exposure and reproductive outcomes, but few studies have investigated the association of chromium exposure and low birth weight (LBW). This study was designed to investigate whether maternal exposure to chromium during pregnancy is associated with an increased risk of LBW. Chromium concentrations in maternal urine samples collected at delivery were measured in 204 LBW cases and 612 matched controls recruited between 2012 and 2014 in Hubei Province, China. Risk of LBW was associated with higher levels of chromium in maternal urine [adjusted odds ratio (OR) = 1.77 for the medium tertile, 95% confidence interval (CI): 0.95, 3.29; adjusted OR = 2.48 for the highest tertile, 95% CI: 1.33, 4.61; P trend = 0.01]. The association was more pronounced among female infants (adjusted OR = 3.67 for the highest tertile, 95% CI: 1.50, 8.97) than among male infants (adjusted OR = 1.22 for the highest tertile, 95% CI = 0.48, 3.11) ( p heterogeneity = 0.06). Our findings suggest that maternal exposure to higher levels of chromium during pregnancy may potentially increase the risk of delivering LBW infants, particularly for female infants. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) and its substitute bisphenol S (BPS) are endocrine-disrupting chemicals and metabolized rapidly in human body. BPA exposure in late pregnancy has been suggested to be associated with preterm birth (PTB), but the associations of trimester BPA and BPS exposures with gestational age have been rarely studied. We aimed to examine maternal urinary BPA and BPS levels longitudinally measured across pregnancy in relation to gestational age and PTB. A prenatal cohort study was conducted between 2014 and 2015 in Wuhan, China. Maternal urinary BPA and BPS concentrations were measured in a complete series of urine samples collected in the 1st, 2nd and 3rd trimesters from 850 pregnant women and corrected by specific gravity. In comparison with the lowest tertile of maternal urinary BPA, higher levels of averaged BPA concentration across pregnancy was associated with a 1.97-day decrease in gestation (95% CI: 3.25, −0.68) and an adjusted odds ratio of 3.19 (95% CI: 1.00, 10.45) for PTB. Higher BPA concentrations in three trimesters were also negatively associated with gestational age and positively correlated with PTB. In contrast, only a positive association of third-trimester BPS with gestational age was found, but the significant association disappeared in the adjusted models. Both maternal trimester and averaged BPA exposure across pregnancy were significantly associated with shortened gestation and increased risk of PTB. However, the results showed little evidence of a relationship between BPS and PTB. • Urinary BPA and BPS were measured in each trimester from 850 pregnant women. • Both trimester and averaged BPA exposure were associated with decreased gestation. • BPA exposure was related to increased risk of preterm birth (PTB) across pregnancy. • BPS exposure across pregnancy was not related to pregnancy duration or PTB. [ABSTRACT FROM AUTHOR]