The inverse association between circulatory placental biomarkers in early pregnancy and maternal body mass index

High maternal body-mass-index (BMI) is linked to adverse pregnancy outcomes, partly through impaired placental development. An inverse association between BMI and placental biomarkers has been described, however it is unclear whether this relationship is restricted to obesity or occurs across the full-BMI range. We assessed the relationship between maternal BMI and placental biomarkers across multiple cohorts. METHODS: We analysed three UK cohorts: ALSPAC (n = 994), CBGS (n = 1202) and POPS (n = 3869). Concentrations of growth-differentiation-factor15 (GDF15), beta-human chorionic gonadotropin (βhCG), pregnancy-associated plasma protein-A (PAPP-A), and alpha-fetoprotein (AFP) were measured at 8-16 weeks of gestation in maternal serum and expressed as gestational age-adjusted z-scores. Cohort-specific regression and individual-participant-data-meta-analyses (IPD-MA) were used. RESULTS: Across cohorts, each 1SD increase in maternal BMI was associated with significant reduction in: GDF15 (β: -0.16, 95%CI: -0.23 to -0.10; p