The fertile phase of the ovulatory cycle is associated with an increased interest in uncommitted sex, according to new research published in Evolution and Human Behavior. But this shift in sexual psychology was not found among women using hormonal contraceptives.
“We wanted to understand whether and how women’s sexual motivations change with ovarian hormones over the ovulatory cycle,” said study authors Talia Shirazi and David Puts, a PhD candidate and associate professor at Pennsylvania State University, respectively.
“For example, one hypothesis suggests that as conception risk increases across the cycle, women’s psychology increasingly directs mating effort toward mates of higher genetic quality. Another hypothesis suggests that changes across the cycle are byproducts of individual differences in reproductive condition.”
“Because each hypothesis makes different predictions about associations between ovarian hormones and mating psychology, we used data on hormone concentrations and facets of mating psychology to evaluate which hypothesis was most strongly supported.”
For their study, the researchers compared 276 women who were currently using hormonal contraception to 353 women who were not. All of the participants were between 18 and 45 years of age.
The women provided saliva samples — which were used to measure estradiol, progesterone, and testosterone — before responding to demographic questions, questions about changes in hormonal contraceptive use, and questions about their sexual behaviors, desires, and preferences. Some of the participants completed this procedure again between 1 and 3 months after the first session.
The researchers found that changes in hormone levels predicted changes in sexual interests among women who were not currently using hormonal contraceptives.
“Interest in uncommitted sex increased as estradiol increased and progesterone decreased within individual female participants. These results are consistent with the idea that ovarian hormones direct mating effort towards short-term, uncommitted sex during the fertile phase of the ovulatory cycle,” Shirazi and Puts told PsyPost. “We also found that women with higher average testosterone levels tended to report greater general sexual desire and interest in uncommitted sex.”
In particular, women with higher estradiol levels and lower progesterone levels were more likely to report having fantasies about having sex with someone they were not in a committed romantic relationship with. But changes in hormones were not associated with changes in general sexual desire.
“Because some prior work suggests that heterosexual women tend to more strongly prefer males of high genetic quality for short-term, uncommitted sex, our results suggest that, in the evolutionary past, cyclic changes in women’s sexual motivations may have functioned in part to recruit genetic benefits for offspring,” Shirazi and Puts said.
However, this was not the case among women who were currently using hormonal contraceptives. “This was a useful experimental control condition, as women on hormonal contraceptives experience smaller fluctuations in hormones across the cycle. The fact that cyclic shifts were not present among users of hormonal contraceptives may also be important to consider for women of reproductive age who are deciding whether or which contraceptive methods to use,” the researchers explained.
But as with all research, the study includes some caveats.
“We recruited a large sample of participants, but we measured hormone levels and sexual motivation only twice for some participants and once for others. Ideally, these variables would be measured more frequently, perhaps even daily. We also can’t be certain that the associations that we observed would be found in other populations because our study largely comprised college-aged women in the US,” Shirazi and Puts explained.
“Perhaps most importantly, although earlier research suggested that women tend to more strongly prefer men of high genetic quality during the fertile phase of the ovulatory cycle, several more recent studies using better study designs have not observed this relationship. There is clearly plenty more research to be conducted in this exciting area!”
The study, “Hormonal predictors of women’s sexual motivation“, was authored by Talia N. Shirazi,, Heather Self,, Khytam Dawood, Kevin A. Rosenfield, Lars Penke, Justin M. Carré, Triana Ortiz, and David A. Puts.