Is nail polish truly a risk for pregnant women?

Pregnancy is a time of significant physiological and hormonal changes. It requires the expectant mother to consider two individuals, herself and her baby, and to be doubly cautious about the products she uses, particularly those related to skincare. Indeed, certain ingredients can penetrate the skin or be inhaled and enter the bloodstream before affecting the health of the fetus. Viewed by some as potential sources of exposure to endocrine disruptors, nail polishes are also under scrutiny regarding their use during pregnancy.

Some nail polishes contain compounds that are controversial during pregnancy.

Among the most concerning ingredients are formaldehyde, toluene, phthalates, and acetone, which can be harmful to fetal health. Formaldehyde is a compound classified by the European Union as a "probable carcinogen". It is also an endocrine disruptor, capable of altering the hormonal system. As for the phthalates found in some nail polishes, they are also suspected of hindering fetal development, particularly by disrupting its hormonal system.

Toluene, on the other hand, is a neurotoxic solvent. Inhalation can lead to neurological disorders. It is also associated with a heightened risk of fetal malformations. A clinical case supports concerns about exposure to toluene during pregnancy. It describes the situation of a newborn with an abnormally large head. A scan conducted in the hours following birth revealed hydranencephaly: a severe brain malformation characterized by the absence of both cerebral hemispheres, replaced by a large cavity filled with fluid. In this case, the mother worked in the automotive industry, where she was exposed to solvents, including toluene, used to clean paints. However, this molecule is also present in some nail polishes. Although it is difficult to establish a direct link between exposure to toluene and this malformation, and the mother's exposure to toluene was much greater than what would occur in a typical nail polish application, this case calls for caution.

Finally, acetone, found in many solvents and in some nail polishes, is a highly volatile solvent that can be easily inhaled. Once absorbed, acetone crosses the placental barrier and can reach the fetus. Although it is metabolized by the liver, a portion of the acetone can still affect the baby's development. Moreover, acetone is known to exacerbate nausea, a common symptom during pregnancy, making its use even more problematic for expectant mothers. The still problematic composition of many nail polishes is the reason why many women choose not to wear nail polish during their pregnancy.

Studies regarding the risks posed by the use of nail polish during pregnancy remain limited and the results are sometimes contradictory. Some research, conducted with very large panels, exceeding 1,000 women, suggest that increased exposure to certain cosmetic products, including nail polish, could be associated with risks of obstetric complications, such as premature births or babies with a birth weight below average. However, other studies, also conducted on a large scale, have not been able to establish such a relationship. It should be noted that these various studies did not specify the frequency of use of cosmetic products nor their composition, factors that are important to consider.

In the absence of definitive data, it is better to apply the principle of caution and avoid manicures during pregnancy.

What about "n-free" nail polishes?

In response to the concerns raised by nail polishes, some brands have developed polishes that aim to be safer, free of formaldehyde, toluene, or phthalates. These are the "n-free" polishes, where n represents the number of problematic ingredients excluded. While these nail polishes may seem appealing to pregnant women, it's important to note that the "n-free" labels are not based on a universally established standard, making it difficult to guarantee their safety during pregnancy.

• FANUCCHI M. & al. Formaldehyde exposure during pregnancy. The American Journal of Maternal Child Nursing (2015).

• ALBOUY-LLATY M. & al. Endocrine Disruptors and Pregnancy: Knowledge, Attitudes and Prevention Behaviors of French Women. International Journal of Environmental Research and Public Health (2017).

• MCGLYNN K. A. & al. Maternal use of personal care products during pregnancy and risk of testicular germ cell tumors in sons. Environmental Research (2018).

• XIAO J. & al. Maternal cosmetics use during pregnancy and risks of adverse outcomes: a prospective cohort study. Scientific Reports (2019).

• AKYOL S. & al. Hydranencephaly in a newborn due to occupational toluene exposure during pregnancy: a case report. Acute and Critical Care (2022).

• RALLIS E. & al. The Risk of Using Cosmetics and Cosmetic Procedures During Pregnancy. Applied Sciences (2024).