Why do women bleed synchronized with the moon's period?

Question

I'm pretty sure that women bleed at every 28 days, which is about the same time taken by the moon to go around the Earth once. Why does that happen? Is it only a coincidence or there is some inter-influence going on?

Answer 1

I don't know for sure, but I reckon it's mediated by the primitive men's hunting expeditions, which they would have to synchronize with the phases of the Moon. So the men would mostly be away hunting, except in new Moon. Those women whose ovulations were synchronized with the men's comings and goings would have a reproductive advantage. The synchronization can't of course be a conscious decision (unlike the men's decision to go out hunting), but it may have been brought about by male pheromones (or maybe it was the result of natural selection, given the reproductive advantage?)
This does not explain why different women ovulate at different times and have cycles of somewhat different lengths, but if women stay closely together for some time, their cycles do converge, I think.
In modern life, women are not in synch with the moon exactly, but that's probably because there is no longer the men's hunting cycle to keep everything in synch.
The near-equality of the female and lunar cycles is probably not just a coincidence.

Answer 2

There are animals that seem to base fertility cycles on the lunar month and there are animals that obviously don't. Certain fish spawn during the full moon. Any possible correlation between human females and the moon has apparently been lost. But this is not to say that it didn't start this way.

Wikipedia has the following to say:

Etymology and the lunar month.
The terms "menstruation" and "menses" come from the Latin mensis (month), which in turn relates to the Greek mene (moon) and to the roots of the English words month and moon — reflecting the fact that the moon also takes close to 28 days to revolve around the Earth (actually 27.32 days). The synodical lunar month, the period between two new moons (or full moons), is 29.53 days long.

A 1975 book by Louise Lacey documented the experience of herself and 27 of her friends, who found that when they removed all artificial nightlighting their menstrual cycles began to occur in rhythm with the lunar cycle. She dubbed the technique Lunaception.[11] Later studies in both humans[12] and animals[13] have found that artificial light at night does influence the menstrual cycle in humans and the estrus cycle in mice (cycles are more regular in the absence of artificial light at night), though none have duplicated the synchronization of women's menstrual cycles with the lunar cycle. One author has suggested that sensitivity of women's cycles to nightlighting is caused by nutritional deficiencies of certain vitamins and minerals.[14]

Some have suggested that the fact that other animals' menstrual cycles appear to be greatly different from lunar cycles is evidence that the average length of humans' cycle is most likely a coincidence.[15][16]

Answer 3

Women are not synchronized with the moon. The timing may sound the same when you say "about the same time", but "about" and "exactly" are worlds apart.

The moon's cycle is 27.3 days from full moon to full moon, and a normal woman's cycle is anywhere from 28 to 32 days.
So even if a woman is perfectly regular every 28 days exactly (to the hour), within 6 months she is out of synch with the moon by 4 days and getting more out of synch each month.

Answer 4

Bird doesn't know what he's talking about ,,,, The menstrual cycle is in no way controlled or effected by the moon phase ,,,, Not every woman is the same anyway ,,,,, Usually the cycle is supposed to appear anywhere from 28 to 30 days ,,,, That's the norm but not all women experience that ,,,, It will very with the person ,,,,

Answer 5

Actually all women are a little different. Some women get there period like clockwork every 28 days, and others miss periods, or don't get their periods very often. Mine used to be every 35 days or so, until I started the pill.

Answer 6

a womans cycle runs approximately each and every 28 days so finally in a team your 28 day era is definite to be on the comparable timeframe at one million element or yet another. in actuality that is only nature being coincidental.

Answer 7

that's nature...