All women with endometrial placental mammals, the accumulation, the animals fertile, but the removal of (menstruated) when the animals infertile.
Some anthropologists question the reconstruction of the endometrium each reproductive cycle energy costs. However, anthropologists made rich Constella Mann does not have the energy savings continue to maintain the endometrium more than offset by having to rebuild in the next reproductive cycle, the lining of the energy costs, and even in many places, such as the lining of the human species is the loss of blood (menstruation public), rather than re-absorption (covert menstruation). However, even in humans, much of it is reabsorbed.
Many people questioned in the evolution of human and related species, an open period, you may lose any advantage endometrial and dismantle, not absorb it, as do most of the blood of mammals related to speculation.
In 1971, a number of studies have shown that cohabitation has become the human female menstrual cycle synchronization. Suppose, in the hunter-gatherer society; men will continue the family hunting trip in the number of female anthropologists is menstruation, speculation; women will not be accepted sexual relations, and menstruation. However, the synchronization period of the existence of significant is controversy.
Human beings do, in fact, about two-thirds of each cycle, the endometrium re-absorption. Strassman said the occurrence of menstruation is not open because it itself is beneficial. In contrast, fetal development, these species require a more developed endometrium, a complete re-absorption is too thick. Strassmann associated species, with a clear period of the uterus that have a large relative to adult female body size.
Many religions have menstruation-related traditions. These may be prohibited during menstruation some operations (such as Orthodox Judaism, Hinduism and Islam have sexual intercourse), or the month after the end of the ceremony (such as “mikvah” Judaism and the large net in the “executive” in the Islamic teach). Some of the traditional social isolation of women in the home, “menstrual hut”, that is, until the end of their menstrual period to retain the sole purpose.
Since the late 1960s, some women choose to control long-term birth control hormones in menstrual frequency. This gives women a few months ahead of schedule, when either she will serve as co-hormonal contraceptives in the 28-day menstrual cycle, hormonal pills taken 21 pills seven days from the rest, or seven placebos during this period, the woman menstruates. If DEPO – Provera injections became available in the 1960s, such as the 1980s and early 2000s combined with progestin oral contraceptive implant Norplant cycles.