Systematic Review and Meta-analysis of Birth Weight and Prenatal Exposure to Perfluoroundecanoic Acid
Background: Due to transplacental exposure to perfluoroundecanoic acid (PFUnDA), there is a need to evaluatepotential developmental effects in humans. We examined the association between PFUnDA exposure and birthweight (BW) using systematic review methodology.Methods: We used a random effects model with inverse-variance weighting to meta-analyze associations betweenPFUnDA exposure biomarkers and changes in BW. We report a pooled estimate and stratified estimates based onfactors including study confidence and timing of sample collection.Results: We detected a pooled mean BW deficit (β) of 15.3 g (95%CI: − 23.4, − 7.1) per ln(ng/mL) PFUnDA increase in our primary analysis of 28 studies. We observed deficits in 5 low (β = − 26.3 g, 95%CI: − 56.5, 3.8), 14medium (β = − 16.5 g, 95%CI: − 26.8, − 6.1), and 9 high confidence studies (β = − 10.3 g, 95%CI: − 24.8, 4.1). Themagnitude of the pooled BW deficit varied across sample timing categories, with the largest average deficit ineight studies with postpartum samples (β = − 21.0 g, 95%CI: − 43.8, 1.8) and the smallest among eight studieswith early pregnancy samples (β = − 6.8 g, 95%CI: − 21.5, 7.9).Conclusions: We observed lower BW associated with higher PFUnDA exposure. Although confidence intervalsoverlapped across strata, we detected smaller BW deficits in higher quality studies and larger deficits amongstudies that collected samples in late pregnancy or postpartum. These trends may be partly explained by biasfrom pregnancy hemodynamics. Future studies conducted in populations with serial pregnancy PFUnDA measures would facilitate data interpretation and address some methodological challenges.