Menstrual cycle and the Moon

[Steve Johnson <***>]

Sorry if this is off topic. I was browsing Rosen
archives and among other things I read Judith's
comment regarding how Rosen always pointed out the
things that nobody knows.

As an example she mentioned the sychronization of
menstrual cycles among female housemates. As I was
thinking about it I also started wondering why the
length of the human menstrual period coincides with
that of the lunar cycle. This is such a basic human
experience that I was sure that this was well
researched and explained. To my astonishment my trusty
Google search turned up mostly new age drivel and few
scientific articles no matter how I composed my search
query. The only two somewhat logical suggestions (but
still very shaky) that I saw were:

1) In the evolutionary environment the ovulation
period coincided with the dark phase so that women's
sexual desire was least when the moon is bright thus
putting pressure on the males to spend less time on
mating and more on hunting while the moon was bright.

2) Some vague statements that all life was marine in
the beginning and thus affected by the tides caused by
moon's gravity. The connection with the homo sapiens
menstrual cycle was left to the reader.

What are the leading evolutionary explanations for why
the menstrual cyclce coincides in length with the
lunar one? I would appreciate any pointers.

P.S.  I also stumbled on several women's medical
discussion board where many women commented on
increased anxiety and stress caused by the full moon.
Any established explanations for this?

- Steve




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