The association of repeated measurements of prenatal exposure to triclosan with fetal and early-childhood growth

Background: Triclosan (TCS) is known to possess endocrine disrupting properties and metabolize rapidly in the human body. Human data concerning repeated measurements of TCS throughout pregnancy in relation to fetal and childhood growth are sparse. Objectives: We investigated the associations between multiple measurements of maternal urinary concentrations of TCS during pregnancy and fetal and early-childhood growth. Methods: The study population included 850 mother-infant pairs who participated in a prenatal cohort established between 2014 and 2015 in Wuhan. Prenatal TCS exposure was measured in a complete series of urine samples collected at the first, second and third trimesters. General linear models and generalized estimating equation models were applied to evaluate the associations of the averaged maternal urinary concentrations of TCS over trimesters and trimester-specific urinary TCS with the z-scores of estimated fetal weight, head circumference, abdominal circumference, and femur length at 16, 24, and 31 gestational weeks, weight and length at birth, and weight and height at 0.5, 1, and 2 years of age. Results: In overall infants, we did not observe any significant association of the averaged maternal urinary concentrations of TCS over trimesters with ultrasound parameters and size at birth. However, a positive association of borderline statistical significance was found between averaged prenatal TCS exposure and the thirdtrimester estimated fetal weight z-score in girls in sex-stratified analyses (beta = 0.054, 95% CI: -0.005, 0.113, p = 0.07). Moreover, averaged prenatal TCS exposure was positively associated with 2 year-old weight z-score among total infants (beta = 0.046, 95% CI: 0.005, 0.087). After stratifying by sex, the same association was observed in girls with more prominent estimation (beta = 0.062, 95% CI: 0.000, 0.124), whereas the association weakened and became not significant in boys (beta = 0.033, 95% CI: -0.024, 0.089). TCS exposure at 1st and 2nd-trimester were positively associated with weight z-score at 2 years, in both overall and female infants. Conclusions: Prenatal exposure to triclosan was associated with elevated third-trimester estimated fetal weight and 2 year-old weight z-score in girls, and the early and middle stage of pregnancy may be the windows of vulnerability. Apart from these findings, we did not find strong evidence for prenatal triclosan exposure in relation to fetal and early-childhood growth.