Phthalates are known endocrine disrupting chemicals. In order to limit exposure, it is important to ascertain the major sources of phthalates.

A study published recently in Science of the Total Environment assessed 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. A birth cohort study was conducted from 2012 to 2015. Usage patterns of PCPs were accessed using structured questionnaires during the third trimester of pregnancy. Spot urine samples were obtained at each trimester, and levels of eleven phthalate metabolites were measured using liquid chromatography tandem mass spectrometry. The association of PCPs use with urinary phthalate metabolite concentrations was evaluated.

In all, 281 pregnant women who provided two or three urine samples across pregnancy were included. Levels of several phthalate metabolites were found to be significantly correlated with the use of PCPs, especially leave-on PCPs. With 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 were exposed to higher concentrations of mono-ethyl phthalate (MEP). There was a positive trend regarding the number of leave-on PCPs used and the change in MEP concentrations. Other positive associations included MBzP and body lotions (7.9%; 95% CI: 0.1%, 16.2%). Concerning rinse-off PCPs, there was a positive association between urinary MBzP and shampoo use, and a negative association between urinary MMP and face wash.

The study concluded that leave-on PCPs were a more probable source of phthalate exposure than rinse-off PCPs. Therefore, pregnant women must reduce the frequency of use of leave-on PCPs to avoid such phthalate exposure.