Critical Windows for Associations between Manganese Exposure during Pregnancy and Size at Birth: A Longitudinal Cohort Study in Wuhan, China

Abstract

Background: Prenatal overexposure to manganese (Mn), an essential micronutrient, is related to impaired fetal growth and development. Fetuses appear to be highly sensitive to Mn during short periods of gestation. However, little is known about the critical windows of susceptibility to Mn for humans. Objectives: Our objective was to estimate trimester-specific associations of exposure to Mn with size at birth. Methods: Urine samples of 3,022 women were collected repeatedly in the first, second, and third trimesters in Wuhan, China. Urinary concentrations of Mn and other toxic metals were measured using an inductively coupled plasma mass spectrometry. Trimester-specific associations of specific gravity–adjusted urinary Mn concentrations with birth weight, birth length, and ponderal index were estimated using multivariable linear regressions with generalized estimating equations. Linear mixed models were applied to evaluate the windows of susceptibility to Mn exposure by comparing the pattern of Mn exposure among newborns with restricted size at birth to those without. Results: When compared with the third quintile of urinary Mn concentrations, both higher and lower quintiles of urinary Mn concentrations in the second and third trimesters were related to reduced birth weight, birth length, and ponderal index. But the observed associations for higher quintiles were stronger and more likely to be statistically significant [e.g., for women who were in the fifth quintile of Mn concentration in the third trimester, the reduction in birth weight was (95% CI: , ) g and in birth length was (95% CI: , 0.00) cm]. Moreover, newborns with restricted size at birth, compared with those without, had higher levels of Mn exposure in the second and third trimesters. Conclusions: This prospective prenatal cohort study revealed an association of exposure to Mn during pregnancy, especially late pregnancy, with restricted size at birth. Replications are needed. https://doi.org/10.1289/EHP3423

Trimester-specific effects of maternal exposure to organophosphate flame retardants on offspring size at birth: A prospective cohort study in China

“…55 Several investigations have suggested significant and strong relationships between exposure to environmental pollutants (e.g., bisphenols, arsenic) in the third trimester and birth outcomes, while null or weaker associations were observed in other trimesters. 56,57 More studies should be done to validate our results.…”

Prenatal Exposure to Disinfection Byproducts and Intrauterine Growth in a Chinese Cohort

“…We constructed GA-specific standard deviation scores (z-scores) for fetal growth parameters based on both ultrasound and birth measures using the GAMLSS package in R software. , Briefly, we modeled AC, HC, BPD, FL, and fetal weight (EFW and birth weight combined) using a cubic spline by GA in days based on our study population after normalizing the parameters using Box–Cox transformations. The fetal growth z-scores were acquired based on the best-fitting models according to Akaike’s information criteria, which represented the percentile of the fetal or birth size at any specific GA …”

“…34,35 Briefly, we modeled AC, HC, BPD, FL, and fetal weight (EFW and birth weight combined) using a cubic spline by GA in days based on our study population after normalizing the parameters using Box−Cox transformations. The fetal growth z-scores were acquired based on the bestfitting models according to Akaike's information criteria, which represented the percentile of the fetal or birth size at any specific GA. 36 Covariates. At recruitment, we obtained basic characteristics of study participants via self-reported questionnaire, which included age, height, marital status, education level, income, geographic residence setting, sources of drinking water, and reproductive history.…”

Optimization of bacterial bioaugmentation for groundwater Mn removal using a waste-based culture medium and lyophilization

“…The exposure to high levels of Mn may be associated not only with neurological disorders such as Alzheimer's disease, Parkinson's disease and Huntington's disease [3][4][5] , but also, consumption of Mn-contaminated water impacts on children's neurodevelopment triggering changes in the intelligence quotient (IQ) and producing attention-deficit hyperactivity disorders 6,7 . Furthermore, the overexposure to Mn during pregnancy leads to significant reductions in size, length and weight of newborns 8 .…”