The average woman will have 500 menstrual cycles throughout her lifetime.1 Although menstruation typically doesn’t win the “favorite days of the month award,” the actual purpose of a woman’s cycle is to prepare her body for conception and procreation. Yet, the irony in Mother Nature’s plan is that the actual window of potential conception only lasts for roughly 2-4 days throughout the 28 day cycle. Among researchers, we call these few days the “period of high fertility,” or the time when women are most likely to conceive.
Many women (and probably even some men!) may have noticed that the days leading up to menstruation can be accompanied by mood swings (you’ve heard of PMS – right?). Yet, there’s a bundle of evidence showing that women’s moods, behaviors, and interpersonal styles actually change during that small window of high fertility as well. For example, during those few days (compared to other days in the cycle) women are more likely to dress sexy,2 they are more accepting of men’s advances,3 they prefer the scent of symmetrical4 and dominant men,5 and they’re even more likely to fantasize about someone other than their current boyfriend or spouse!6