Associations between prenatal per- and polyfluoroalkyl substances (PFAS) exposure and fetal growth measurements in utero and at birth in the LIFECODES cohort: 2006-2019.

INTRODUCTION

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals used in consumer and industrial products, and have been linked with adverse pregnancy outcomes, including altered fetal growth. Few studies, however, have investigated associations between PFAS and longitudinal measures of fetal growth.

OBJECTIVE

Examine associations between prenatal PFAS and ultrasound measures [femur length (FL), head circumference (HC), abdominal circumference (AC)], and birthweight outcomes in the LIFECODES birth cohort.

METHODS

This study included 1220 participants from nested case-control studies within the LIFECODES cohort. We used generalized estimating equations to evaluate associations between six PFAS and repeated fetal growth measurements converted to gestational age (GA)-specific Z-scores, while multivariable linear and logistic regression models assessed associations with birthweight and size-for-GA [small-for-GA (SGA) and large-for-GA (LGA)], respectively. The effect of PFAS mixture was examined using quantile-based g-computation (qgcomp). All models were adjusted for maternal age, race/ethnicity, educational attainment, health insurance status, pre-pregnancy body mass index, parity, enrollment year, fetal sex, and aspects of study design.

RESULTS

An interquartile range increase in perfluorooctanoic acid (PFOA) was associated with a 0.10 standard deviation (SD) increase in FL Z-score (95% CI: 0.02, 0.18). Positive associations with FL were more pronounced among African American participants [SD change: 0.26 (95% CI: -0.01, 0.53)] and male fetuses [SD change: 0.16 (95% CI: 0.05, 0.28)]. Qgcomp analyses showed similar positive associations with FL. Associations with birthweight outcomes were generally inconsistent, with certain PFAS associated with increased odds of LGA among females, while some PFAS were linked to lower odds of SGA across sexes.

CONCLUSIONS

Prenatal PFAS exposure was modestly associated with increased FL, with some variations by fetal sex or maternal race. Future research should examine underlying biological mechanisms, clinical implications, and the influence of modifying factors such as psychosocial stress and maternal diet on the observed associations.