Relationship between the Menstrual Cycle and Sexual Activity: Maybe Women Do Not Lose Estrus

This study examines the relationship between the menstrual cycle and women's sexuality, focusing on evolutionary and hormonal influences. Two datasets were utilized, with the first involving 489 women over 18 years old. The goal was to assess sexual libido characteristics on the day participants completed the survey, collecting data on sexual intercourse frequency, masturbation frequency, average libido score, and the average number of initiators of sexual activity. The menstrual cycle was divided into follicular and luteal phases, assuming ovulation occurred on the 14th day after the first day of menstrual bleeding. Each phase was further divided into early and late subgroups. The study hypothesized that preovulatory (follicular) sexual activity would differ from the nonfertile (luteal) phases. Notably, the frequency of women initiating sexual intercourse during the early follicular phase showed significant differences. Granger causality analysis was employed to explore the causal relationship between hormonal changes (FSH, LH, progesterone, estradiol) and sexual motivations, revealing a strong linear relationship between estradiol levels and the frequency of women initiating sexual activity.