Reproductive
Hair Relaxer Use and Anti-Mullerian Hormone Concentrations in a North American cohort Lauren A. Wise* Lauren A. Wise Ruth J. Geller Dmitrii Krivorotko Geralyn Lambert-Messerlian Amelia K. Wesselink
Introduction: Hair relaxers (chemical straighteners) are used by millions of North Americans, particularly people of color. Relaxer use has been associated with an increased risk of hormone-dependent reproductive outcomes, including early puberty, subfertility, and uterine fibroids. The effect of hair relaxer use on concentrations of anti-mullerian hormone (AMH), a biomarker of ovarian reserve, has not been studied.
Methods: We analyzed baseline data from Pregnancy Study Online (PRESTO), a preconception cohort study of North American pregnancy planners (2015-2024). We restricted analyses to 838 females aged 21-44 years without a diagnosis of PCOS. Participants reported on lifetime hair relaxer use including age at first use, frequency and duration of use, and number of burns. We assayed AMH concentrations using picoAMH (Ansh labs). We used modified Poisson regression to estimate prevalence ratios (PR) and 95% CIs for associations between hair relaxer use and low AMH (<1.8 ng/ml to denote low AMH corresponding to <20% without evidence of polycystic ovarian morphology), adjusted for age, race, ethnicity, BMI, smoking, and history of subfertility.
Results: Overall, 2% of participants were current users and 10% were former users of hair relaxers; 15% of ever users began at ages <10 years. Median AMH was 5.5 ng/ml. Compared with never use of hair relaxers, PRs for current and former use were 2.01 (95% CI: 0.74-5.44) and 0.85 (95% CI: 0.54-1.34), respectively. Among ever users, prevalence of low AMH was highest for those with the greatest frequencies and durations of use (≥3 times/year vs. never use: PR=1.52, 95% CI: 0.65-3.56; ≥10 years vs. never use: PR=1.47, 95% CI: 0.46-4.67; frequency ≥3 times/year + duration ≥5 years vs. never use: PR=1.28, 95% CI: 0.51-3.18). No appreciable associations were seen with age at first use or number of burns.
Conclusion: Some measures of hair relaxer use were associated with a higher prevalence of low AMH, though precision was limited.