Environment/Climate Change
Trajectories of prenatal phthalate exposure and associations with gestational weight gain and infant birthweight – Findings from an Ethnically Diverse U.S. Pregnancy Cohort (2010-2015). Shabnaz Siddiq* Shabnaz Siddiq Jeanette A. Stingone Andrew Rundle John Meeker Virginia Rauh Susannah Leisher Pam Factor-Litvak
Background:
We assessed trajectories of prenatal phthalate metabolites (PthM) and their associations with gestational weight gain (GWG) and birthweight in a diverse U.S. sample.
Methods:
We analyzed 951 controls (without pregnancy complications) from a nested matched case control study embedded in the Nulliparous Mothers to Be Study who provided 1-3 urine samples (total n=2723) throughout pregnancy. Eleven PthM were investigated. Maternal weight was recorded prospectively once per trimester, and birthweight (in grams) was recorded at delivery. We applied latent class growth analysis (LCGA) to identify trajectories of PthM exposure and estimated associations with total GWG and infant birthweight, adjusting for confounders Analyses were stratified by maternal BMI, race/ethnicity, and infant sex.
Results:
We identified stable trajectories for high-molecular-weight and low-molecular-weight phthalates, while replacement PthM showed temporal changes throughout pregnancy, reflecting distinct exposure patterns. Higher Monobenzyl phthalate (MBzP) trajectories which indicated increases in the second or third trimester were associated with lower total GWG compared to low-exposure trajectory (i.e 2.5-4.0 lb decrease). Stronger associations were found in obese compared to non-obese women, in non-Hispanic Black women and Hispanic women compared to Non-Hispanic White women, and women delivering female compared to male infants. Higher Mono-isobutyl phthalate (MiBP) trajectories were associated with lower infant birthweight (i.e. 87 gram decrease), with stronger effects observed among underweight/normal weight women, Hispanic women, and women carrying female infants.
Conclusions:
Higher MBZP and MiBP trajectories were associated with lower GWG and infant birthweight. While most infants were born within the healthy birthweight range, these findings suggest certain PthM trajectories could affect maternal and fetal health