Pregnancy blood pressure trajectories in relation to high PFAS exposure: A longitudinal study from the Ronneby Mother-Child Cohort

Introduction: Maternal blood pressure (BP) is crucial for the health of both mother and fetus, with long-term implications for the child's health. Studies exploring the link between perfluoroalkyl substances (PFAS) exposure and hypertensive disorders of pregnancy often yield inconsistent results, frequently focusing on a single BP measurement rather than longitudinal measurements. This study characterized the systolic and diastolic BP trajectories during pregnancy and determined their association with PFAS exposure in Ronneby, Sweden, where a third of the population was highly exposed from contaminated drinking water. Methods: We used longitudinal data from the Ronneby Mother-Child Cohort. Nine PFAS compounds were measured in a serum sample collected during pregnancy and BP measurements were taken as part of the routine pregnancy monitoring program. BP trajectories were identified by Group Based Trajectory Modelling. Odds ratios (OR) for membership in each trajectory by PFAS quartiles were calculated via multinomial logistic regression models and Quantile G-computation was applied to quantify the joint effect of PFAS. Results: The study comprised 214 women with 1705 BP measurements. PFOS and PFHxS were detected at the highest concentrations (medians 16.6 and 10.2 ng/mL). Trajectory analysis identified a cubic shape three-trajectory solution, with one trajectory having elevated BP throughout pregnancy. Higher PFAS concentrations seemed to increase the probability of belonging to the high-BP trajectory in both single-pollutant and multi-pollutant models. Conclusions: Higher PFAS exposure was associated with an increased OR of an adverse BP trajectory, underscoring the importance of monitoring pregnancy BP in communities with elevated PFAS exposures.