Association of in utero hexachlorocyclohexane exposure with gestational age

As endocrine disrupting chemicals, hexachlorocyclohexane (HCH) isomers were reported to impair the intrauterine growth. Although the findings of HCHs with preterm birth were well established, the associations with gestational age were limited. In the present study, we examined whether exposure to HCHs would influence gestational age. The study population included 1028 pregnant women and their offspring who were born in 2014-2015 from a birth cohort in Wuhan, China. Associations of the cord serum HCH levels with gestational age were estimated using generalized linear models. We found higher HCH levels in pregnant women, who were elder, had higher body mass index (BMI) before pregnancy, received higher education, or were exposed to smoking passively. For term birth, the 3rd tertiles of α-HCH and γ-HCH were significantly associated with shorter gestational age [crude β = -1.017, confidence interval (CI): - 2.017, - 0.018 for α-HCH, crude β = -1.068, CI: - 2.067, - 0.070 for γ-HCH], and relationships were similar after adjusted by covariates. Stratified analysis showed positive associations between α-HCH and gestational age for mothers younger than 25 years old (adjusted β = 0.610, CI: 0.061, 1.158), while showing negative relationships for mothers elder than 35 years old (adjusted β = -1.365, CI: -2.414, -0.317). In summary, our results indicated cord serum levels of HCHs were associated with gestational age at birth.