Gestational bisphenol S impairs placental endocrine function and the fusogenic trophoblast signaling pathway

Obesogenic Endocrine Disrupting Chemicals: Identifying Knowledge Gaps

Endocrine disrupting chemicals (EDCs) are compounds that are part of everyday consumer products and industrial manufacturing processes. EDCs can interfere with the endocrine system, including the adipose tissue. Accumulating evidence from epidemiological, animal, and in vitro studies demonstrates that EDCs can alter body weight, adipose tissue expansion, circulating lipid profile, and adipogenesis, with some resulting in transgenerational effects. These outcomes appear to be mediated through multiple mechanisms, from nuclear receptor binding to epigenetic modifications. A better understanding of the signaling pathways via which these EDCs contribute to an obesogenic phenotype, the interaction amongst complex mixtures of obesogenic EDCs, and the risks they pose relative to the obesity epidemic are still needed for risk assessment and development of prevention strategies.

Maternal and paternal preconception exposure to bisphenols and size at birth

STUDY QUESTION

Are maternal and paternal preconception urinary bisphenol A (BPA) or bisphenol S (BPS) concentrations associated with offspring birth size?

SUMMARY ANSWER

Maternal-but not paternal-preconception urinary BPA concentrations were associated with lower birth size among couples seeking fertility evaluation.

WHAT IS KNOWN ALREADY

Prenatal BPA exposure has been previously associated with reduced birth size in some but not all epidemiologic studies. However, the potential effect of BPA exposure before conception in either parent is unknown. Data on BPS is practically absent.

STUDY DESIGN, SIZE, DURATION

Ongoing prospective preconception cohort of women and men seeking fertility evaluation between 2005 and 2016 in a large fertility center in an academic hospital in Boston, MA, USA.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We examined the association between maternal and paternal preconception, as well as maternal prenatal urinary BPA and BPS concentrations, and size at birth among 346 singletons from couples recruited in the Environment and Reproductive Health (EARTH) Study using multivariable linear regression. Infant birth weight and head circumference were abstracted from delivery records. Mean preconception and prenatal exposures were estimated by averaging urinary ln-BPA and ln-BPS concentrations in multiple maternal and paternal urine samples collected before pregnancy, and maternal pregnancy samples collected in each trimester.

MAIN RESULTS AND THE ROLE OF CHANCE

Maternal preconception urinary BPA concentrations were inversely associated with birth weight and head circumference in adjusted models: each ln-unit increase was associated with a decrease in birth weight of 119 g (95% CI: -212, -27), and a head circumference decrease of 0.72 cm (95% CI: -1.3, -0.1). Additional adjustment by gestational age or prenatal BPA exposure modestly attenuated results. Women with higher prenatal BPA concentrations had infants with lower mean birth weight (-75 g, 95% CI: -153, 2) although this did not achieve statistical significance. Paternal preconception urinary BPA concentrations were not associated with either birth weight or head circumference. No consistent patterns emerged for BPS concentrations measured in either parent.

LIMITATIONS, REASONS FOR CAUTION

We observed a strong negative association between maternal-but not paternal-preconception BPA concentrations and offspring birth size among a subfertile population. Although these results are overall consistent with prior studies on prenatal BPA exposure, these findings may not be generalizable to women without fertility concerns.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests that the unexplored maternal preconception period may be a sensitive window for BPA effects on birth outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

Work supported by Grants (ES R01 009718, ES 022955 and ES 000002) from the National Institute of Environmental Health Sciences (NIEHS). C.M. was supported by a post-doctoral fellowship award from the Canadian Institutes of Health Research. There are no competing interests to declare.