| Summary: | 碩士 === 國立陽明大學 === 環境與職業衛生研究所 === 103 === Bispheonl A (BPA) is used mainly in the production of polycarbonate plastics and epoxy resins and has been widely used in daily life, such as plastic products, food and beverage can linings, baby bottles, thermal receipts and dental sealants. BPA is an environmental hormone with proven endocrine-disrupting effects that may cause adverse effects on human health. Prenatal exposure to BPA has been associated with adverse fetal development and birth outcomes.
The aim of this study was to establish a pregnant cohort to explore the association between maternal BPA exposure levels and fetal developments and birth outcomes. A pregnant cohort was follow-up. Maternal urine samples were collected at the first, second, and third trimester. BPA concentrations were determined for every specimen by using ultra performance liquid chromatography coupled with a Q-Tof mass spectrometer and adjusted by creatinine concentrations. Fetal growth charateristics were repeatedly measured by ultrasonic scan and birth outcomes were assessed by a pediatrician.
A total of 201 pregnant women consented to participate and 162 pregnant women were followed until delivery. Due to insufficient urine volume, 87 pregnant women having completed specimens and sufficient urine volume in all three trimester were analyzed in this study. After adjusting for the urinary creatinine concentration, the GM of BPA concentrations during the three trimesters were 0.17μg/g cre., 0.37μg/g cre., and 0.34μg/g cre., respectively. No statistically significant correlations between urinary BPA concentrations and gestational ages or maternal body weights were observed in a mixed effects model using a generalized estimating equation. The urinary BPA concentrations of pregnant women in the first trimester were negatively correlated with fetal biparietal distance (r=-0.23) and fetal femur length (r=-0.24) during gestational weeks 19-21. But after adjusting covariates, there were no statistically significant correlation between urinary BPA concentration during the three trimesters and fetal development. No statistically significant association existed between maternal BPA concentration in each trimester and sex, preterm status, or low birth weight. Data analyzed further stratified women by the 75th percentile urinary BPA concentrations in the first, second, and third trimester. Pregnant women in the group with above-75th during the third trimester had short neonatal head circumference in the multivariable regression model (β=-0.52, p-value=0.04). High BPA level in the second trimester had a significant negative association with neonatal birth weight especially in the primiparas (β=-304.82, p-value=0.03).
These results indicated that maternal BPA exposure might decrease fetal length at birth and birth weight. Primiparas are especially at risk, and second trimester of pregnancy may be the critical stage of exposure. In spite of that previous studies have shown inconsistent results and the limitated subjects of this study, further study to clarify the correlation between prenatal exposure to BPA and fetal growth and birth outcomes is warranted.
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