Objective: To determine if red-haired infertile women have an increased prevalence of endometriosis. Design: Prospective, nonblinded. Setting: Large, metropolitan, private hospital, associated with a university. Subspeciality care provided by reproductive endocrinologists. Patients: One hundred forty- three consecutive women undergoing laparoscopy or laparotomy for infertility. Interventions: Laser ablation of any endometriosis present. Main Outcome Measure: Presence of endometriosis. Results: Of 143 women entered into the study, 12 had natural red hair. The ages of these women ranged between 23 and 41 years. Ten of 12 (83%) of the red-haired women were found to have endometriosis compared with 55 of 131 (42%) of nonredheads. By statistical analysis, the 95% confidence intervals for the presence of endometriosis in redheads was 55% to 100% versus 34% to 51% for nonredheads. Conclusion: The results suggest an association between the occurrence of natural red hair and those factors that lead to the development of endometriosis.
Woodworth, S. H., Singh, M., Yussman, M. A., Sanfilippo, J. S., Cook, C. L., & Lincoln, S. R. (1995). A prospective study on the association between red hair color and endometriosis in infertile patients. Fertility and Sterility, 64(3), 651–652. https://doi.org/10.1016/S0015-0282(16)57809-1