Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Family Medicine, Kaohsiung Medical University, Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. Electronic address: [Email]
BACKGROUND : Fetuses are susceptible to phthalates, known endocrine disrupting chemicals, within sensitive windows of development. It is crucial to determine the major sources of phthalates to reduce exposure. This study aims to examine the associations between usage patterns of personal care products (PCPs) and urinary levels of phthalate metabolites across pregnancy in a multi-hospital based birth cohort. METHODS : During 2012-2015, we conducted a birth cohort study named the Taiwan Mother Infant Cohort Study (TMICS). Usage patterns of PCPs were obtained using structured questionnaires during the third trimester of pregnancy. Spot urine samples were collected at each trimester, and levels of eleven phthalate metabolites were measured by liquid chromatography tandem mass spectrometry. The association of PCPs use with urinary phthalate metabolite concentrations was assessed using GEE models. RESULTS : Among the 1676 pregnant women participated in TMICS, 281 who provided two or three urine samples across pregnancy were included. The levels of several phthalate metabolites were significantly associated with the use of PCPs, particularly leave-on PCPs. With the increasing use of skin toners (11.7%; 95% CI: 1.5%, 22.9%), lipsticks (13.2%; 95% CI: 4.6%, 22.5%), and essential oils (21.8%; 95% CI: 9.1%, 36.0%), individuals are exposed to higher concentrations of mono-ethyl phthalate (MEP). Additionally, a positive trend was found regarding the number of leave-on PCPs used and the measured change in MEP concentrations (P for trend = 0.01). Other positive associations included MBzP and body lotions (7.9%; 95% CI: 0.1%, 16.2%). With regard to rinse-off PCPs, we found a positive association between urinary MBzP and shampoo use, and a negative association between urinary MMP and face wash. CONCLUSIONS : Leave-on PCPs were found to be a more probable source of phthalate exposure than the use of rinse-off PCPs. We suggest pregnant women reduce the frequency of leave-on PCPs use during pregnancy to avoid such phthalate exposure.