Association between Prenatal Phthalate Exposure and Birth Outcomes

Objective: To understand the association between exposure in pregnant women to phthalic acid esters (PAEs) and birth outcomes. Method: The study was conducted from April to June 2013 in Xiamen, China. A total 1020 pregnant women (gestational age <= 16 weeks) met the inclusion criteria and were included in the cohort. Finally, 25 women with premature delivery and 15 with low birth weight were defined as case groups. According to the study criteria, we selected 100 healthy participants as a control group. Participant information was collected by questionnaires and urine samples were collected, and detect five PAEs (MMP, MEP, MBP, MBzP, and MEHP) levels in urine samples. Single and multi-factor logistic analyses were used to analyze the association between PAE concentration and birth outcomes. Results: Medians of the five PAEs above in the premature delivery group were 36.13 ng/ml, 19.02 ng/ml, 13.64 ng/ml, 2.11 ng/ml, 43.47 ng/ml, respectively. In the control group, these were 35.48 ng/ml, 17.62 ng/ml, 10.15 ng/ml, 2.34 ng/ml, 35.62 ng/ml, respectively. The result of multi-factor logistic analysis indicated that MBP and MEHP were associated with premature delivery: OR 1.629, 95% CI (1.067, 2.488), OR 1.675, 95% CI (1.028, 2.729), respectively. Medians of the five PAEs in the low birth weight group were 37.28 ng/ml, 21.36 ng/ml, 14.60 ng/ml, 2.63 ng/ml, 45.72 ng/ml, respectively. In the control group, these were 35.48 ng/ml, 17.62 ng/ml, 10.15 ng/ml, 2.34 ng/ml, 35.62 ng/ml respectively. MEP, MBP, and MEHP were associated with low birth weight: OR 1.699, 95% CI (1.074, 2.688), OR 1.621, 95% CI (1.061, 2.475), and OR 1.817, 95% CI (1.005, 3.284), respectively. Conclusion: MBP and MEHP exposure in pregnant women were risk factors of premature delivery and MEP, MBP, MEHP exposure were risk factors of low birth weight. Preventing or reducing environmental exposure of pregnant women to these PAEs is of utmost importance.