Parabens are a group of related chemicals that are often used as preservatives in cosmetic products. Parabens commonly used in cosmetics include methylparaben, propylparaben, butylparaben, and ethylparaben. Parabens are often used in combination with other preservatives in a product to provide better protection against a broad range of microorganisms. Cosmetics that may contain parabens include makeup, moisturizers, hair care products, and shaving products.1

The effects of parabens on human health have long been debated. FDA continues to review published studies on the safety of parabens.1 Research suggests that exposure to certain common phenols during pregnancy, particularly parabens and triclosan, could possibly disrupt the growth of boys during fetal growth and the first years of life.2 In vitro, parabens have been shown to have estrogenic activities.2 Parabens have also been shown to inhibit aromatase.3

A recent study assessed the association between urinary parabens of pregnant women and gestational diabetes mellitus (GDM) and studied the modification effect of prepregnancy body mass index (BMI). Significant non-linear associations of PrP and the summed estrogenic activity of parabens with GDM were noted in the stratified analysis by prepregnancy BMI in the overweight/obese population. Among overweight/obese pregnant women, moderately higher levels of PrP and summed estrogenic activity of parabens were noted to be significantly associated with an increasing GDM prevalence.4

Parabens are known to be associated with transplacental passage. A study revealed that in cord blood, methylparaben, propylparaben and the sum of all measured parabens were inversely associated with testosterone levels. The negative association of cord blood parabens and testosterone levels suggests possible risks with respect to importance of testosterone for prenatal male development.5 Ethyl paraben has been shown to be associated with increased risk for placental preterm birth.6 A recent study also noted first trimester butylparaben and propylparaben urinary concentrations to be associated with glucose levels in a pregnancy cohort of women at high risk of GDM.7

There is accumulating evidence to suggest transplacental passage of parabens and there possible adverse effects on the growing fetus as well as the mother. It thus seems wise to avoid the use of paraben-containing products during pregnancy.

References

1. Available from: https://www.fda.gov/cosmetics/productsingredients/ingredients/ucm128042.htm. Accessed on March 5, 2019.
2. Philippat C, Botton J, Calafat AM, et al. Prenatal exposure to phenols and growth in boys. Epidemiology. 2014 Sep;25(5):625-35.
3. van Meeuwen JA, van Son O, Piersma AH, et al. Aromatase inhibiting and combined estrogenic effects of parabens and estrogenic effects of other additives in cosmetics. Toxicol Appl Pharmacol. 2008 Aug 1;230(3):372-82.
4. Li Y, Xu S, Li Y, et al. Association between urinary parabens and gestational diabetes mellitus across prepregnancy body mass index categories. Environ Res. 2019 Mar;170:151-159.
5. Kolatorova L, Vitku J, Hampl R, et al. Exposure to bisphenols and parabens during pregnancy and relations to steroid changes. Environ Res. 2018 May;163:115-122.
6. Aung MT, Ferguson KK, Cantonwine DE, et al. Preterm birth in relation to the bisphenol A replacement, bisphenol S, and other phenols and parabens. Environ Res. 2019 Feb;169:131-138.
7. Bellavia A, Chiu YH, Brown FM, et al. Urinary concentrations of parabens mixture and pregnancy glucose levels among women from a fertility clinic. Environ Res. 2019 Jan;168:389-396.