Early Pregnancy BPA Exposure Effects on Gender-Specific Gestational Length and Birth Weight

BPA linked to low birth weights in baby girls

Girls born to mothers with high levels of BPA in their system during the first trimester of pregnancy weigh less at birth than babies with lower exposure, according to a new study.

2015 Study Abstract

Context and Objective:

Effects of prenatal exposure to Bisphenol A (BPA) on gestational and birth outcomes are controversial. The aim of the study was to evaluate the relationship between prenatal exposure to BPA and birth and gestational outcomes.

Design, Setting, Participants, and Outcome:

Levels of unconjugated (uBPA) and BPA glucuronide in 80 matching samples of pregnant women during the first trimester of pregnancy and at delivery and matching term cord blood obtained from a prospective study conducted at the University of Michigan Hospitals were determined using a methodology validated in the National Institutes of Environmental Health Sciences funded Round Robin study and related to pregnancy outcomes.


Highest levels of uBPA were found in maternal term samples followed by first trimester maternal (M1) samples and cord blood. A 2-fold increase in M1 uBPA was associated with 55-g less birth weight when male and female pregnancies were combined and 183-g less birth weight with only female pregnancies. A 2-fold increase in maternal term uBPA was associated with an increased gestational length of 0.7 days for all pregnancies and 1.1 days for only female pregnancies.


Higher uBPA exposure levels during first trimester and term are associated with sex-specific reduction in birth weight and increase in gestational length, respectively. Race, parity, and employment have an effect on BPA exposure. Because low birth weight is associated with adverse health outcomes, effect of early pregnancy BPA levels on reducing birth weight highlights the risk posed by developmental exposure to BPA.

Sources and more information
  • Gender-Specific Effects on Gestational Length and Birth Weight by Early Pregnancy BPA Exposure, Endocrine Society, DOI: http://dx.doi.org/10.1210/jc.2015-1724, September 25, 2015.
  • Pregnant women with high levels of BPA in their blood during their first trimester were more likely to have baby girls with low birth weights, Environmental Health Sciences, September 25, 2015.

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