Placental angiogenic biomarkers in relation to prenatal bisphenol and phthalate exposure

Placental development, involving rapid vascularization, is regulated by concentration gradients of numerous growth factors and hormones. Placental growth factor (PlGF) promotes vasculogenesis and angiogenesis in the placenta, while soluble fms-like tyrosine kinase-1 (sFlt-1) inhibits these processes. An elevated ratio of sFlt-1/PlGF in maternal serum is predictive of preeclampsia. Exposure to two classes of ubiquitous endocrine-disrupting chemicals, bisphenols and phthalates, has also been previously linked to preeclampsia development.

We investigated the relation of urinary concentrations of bisphenols and phthalate metabolites, measured up to three times during pregnancy, with serum concentrations of sFlt-1, PlGF, and their ratio in the New York University Children's Health and Environment Study. Linear mixed models were used to analyze up to three measurements of PlGF and sFlt-1 adjusted for gestational age at the time of serum collection.

We found that higher molar sum concentration of bisphenol A and bisphenol S was associated with lower sFlt-1 (-0.12, 95 % CI: -0.22, -0.03), higher PlGF (0.08, 95 % CI: -0.01, 0.18), and lower sFlt-1/PlGF ratio (-0.12, 95 % CI: -0.21, -0.02). Phthalic acid and metabolites of anti-androgenic and low molecular weight phthalates were similarly associated with higher PlGF and lower sFlt-1/PlGF, but only after 20 weeks of gestation.

The unexpected relationship between prenatal bisphenol and phthalate exposure and lower sFlt-1/PlGF warrants further investigation. Our results suggest that the effect of these endocrine-disrupting chemicals on placental health may be more complicated than what is currently understood through these angiogenic biomarkers.