Increased use of hair products, including dyes, bleach, mousse, and relaxers, were associated with lower levels of sex steroid hormone concentrations in pregnant women, according to findings in a study published in Environmental Research. .Since personal care products (PCPs) often contain endocrine disrupting chemicals such as phthalates and parabens, the purpose of the study was to examine the effects of self-reported PCP use on sex-steroid and thyroid hormone levels during pregnancy.
Researchers enrolled 1070 pregnant women from the Puerto Rican PROTECT Cohort between 2011 and 2017 into their study. They collected blood samples from pregnant women at 18±2 weeks (Visit 1), 22±2,weeks at Visit 2, and again at 26 ±2 weeks (Visit 3). During these visits, the pregnant women also filled out self-report questionnaires which ascertained their use of PCPs within a 48-hour period prior to the blood sample collection, including perfumes, soap, lotions, cosmetics, and other PCPs.
Researchers measured the concentrations of nine hormones found within the prenatal maternal serum samples, including corticotropin-releasing hormone (CRH), sex-hormone binding globulin (SHBG), estriol (E3), progesterone, testosterone, thyroid-stimulation hormone (TSH), total triiodothyronine (T3), total thyroxine (T4), and free thyroxine (fT4).
The researchers analyzed the relationships between PCP use and serum hormone concentrations levels using linear mixed models with random intercepts. Investigators observed lower levels of sex-hormone binding globulin (SHBG) (%Δ = -7.1, 95%CI, 12.4,-1.8), estriol (%Δ = -23.2, 95%CI: -32.2,-13.0), progesterone (%Δ = -21.5, 95%CI, 29.4,-12.9), and testosterone (%Δ = -21.5, 95%CI: -33.1,-7.8) in pregnant women who used hair products compared with pregnant women who did not. They also observed data trends in which cosmetic PCP use significantly increased with age, household income, and education level (P <.01).
The authors stated, “although self-reported questionnaires are appropriate to collect personal habits such as PCP use, participants may not accurately remember exposure and may not have had their typical PCP use routine during the relevant 48-hour timeframe that was captured in the questionnaire. Additionally, the pregnant women may have altered their use of cosmetics prior to conception or immediately after discovering they were pregnant.
Other study limitations included lack of data on PCP use duration, the inability of the investigators to identify specific PCP brands causing the lowered hormone levels, and the inability of the investigators to ascertain whether maternal, fetal, or placental contributions to circulating hormone levels were most affected by PCP-related chemicals.
“These findings are important for identifying populations at risk of potentially harmful PCP-related chemical exposures,”the researchers wrote. “Our results also suggest that chemicals in some hair products may alter sex steroid hormones during pregnancy.” Researchers suggested that “primary physicians and obstetricians should inform and offer guidance to reproductive age women about the potential health impact of endocrine-disrupting chemicals such as those found in hair care products.”
Study results indicated chemicals in some hair products altered sex steroid hormone levels during pregnancy. Pregnant women should be notified that the use of such hair products have the potential to adversely impact pregnancy outcomes so that they can make informed decisions during their pregnancies.
Rivera-Nunez Z, Ashraf P, Barrett ES, et al. Personal care products: Demographic characteristics and maternal hormones in pregnant women from Puerto Rico. Environ Res. Published online November 17, 2021:112376. doi:10.1016/j.envres.2021.112376