Association between Phthalate Metabolites in Cord Blood and Preterm Birth, a Nested Case-Control Study in Tianjin, China

The influences of maternal exposure to endocrine disrupting chemicals on birth outcomes are not well understood. To assess phthalates exposure levels in utero and investigate their associations with preterm birth (PTB)，we performed a case-control study of 30 PTB newborns and 60 matched control newborns from a prospective mother-baby cohort. Control subjects were matched to case subjects by maternal age (+/- 3 years) and birth date. We quantified concentrations of MBP, MBzP, MMP, MEP and MEHP in cord blood. Compared with control infants, the concentrations of MMP, MEP and MEHP in cord blood were significantly higher in preterm newborns. With or without adjusting for potential confounders, MMP, MEHP and high molecular weight phthalate metabolites concentrations above the median levels were observed to be associated with an increased risk of PTB. In our study, prenatal phthalates exposure was related to preterm birth and may be a risk factor.