Additionally, I don’t think it’s all that accurate to say that the incidence of menstruation was that frequent before birth control. My understanding is that bleeding during pregnancy is comparatively rare, though not unheard of, and that significant numbers of women do not menstruate or have a reduction in menstruation during breastfeeding. It is also my understanding that women have traditionally started reproducing not long after the onset of menstruation, or even sooner (the age of menarche appears to be decreasing, but pregnancy is possible prior to a girl’s first period). If these understandings are correct I would expect that the modern Western experience of roughly-monthly ovulation and menstruation is rather novel.
Additionally, I don’t think it’s all that accurate to say that the incidence of menstruation was that frequent before birth control. My understanding is that bleeding during pregnancy is comparatively rare, though not unheard of, and that significant numbers of women do not menstruate or have a reduction in menstruation during breastfeeding. It is also my understanding that women have traditionally started reproducing not long after the onset of menstruation, or even sooner (the age of menarche appears to be decreasing, but pregnancy is possible prior to a girl’s first period). If these understandings are correct I would expect that the modern Western experience of roughly-monthly ovulation and menstruation is rather novel.