Intrasexual competition: effects of hormonal contraceptives

Women’s intrasexual competition has been shown to fluctuate with fertility status, and in particular, with testosterone. It’s increasingly common that women take some form of hormonal contraceptives, especially the combined oral contraceptive (COC) pill which has been shown to decrease testosterone levels. Progesterone-only methods such as the implant or shot have been shown to have higher levels of free testosterone compared to the pill. The current study investigates the differences in intrasexual competition between pill users and progesterone-only users. 773 women took several surveys that obtained their information regarding menstrual cycle, contraceptive use, relationship status, and also took the Scale for Intrasexual Competition. Results show that women using the COC pill had higher levels of intrasexual competition than women using the implant or shot. However, no effect of relationship status was found. This study adds to a growing body of literature about the behavioral effects of hormonal contraceptives