Prenatal phthalate exposure in relation to gestational age and preterm birth in a prospective cohort study

This study enrolled 3266 pregnant women, to explore the relationship of prenatal phthalate exposure with the risk of preterm birth and gestational age. All participants filled questionnaires and provided with up to three urine samples during three trimesters. Seven phthalate metabolites in urines were measured. The incidences of very preterm, late preterm, early-term, late-term and postterm births were 0.58%, 3.52%, 24.22%, 10.53%, and 0.34%, respectively. Non-linear relationships were shown between phthalate metabolites and gestational age. Except for monomethyl phthalate (OR = 1.65, 95%CI = 1.17–2.34), the average concentrations of phthalate metabolites were associated with a slightly and insignificantly increased risk of overall preterm birth ( 0.05) or a non-linear manner (p-value