On p.169 of my edition of de Beauvoir's The Second Sex, she includes a footnote remarking
The moon is a source of fertility; it is seen as the "master of women"; it is often believed that the moon, in the form of a man or a snake, couples with women. The snake is an epiphany of the moon;...it watches over holy sources, the Tree of Life, the Fountain of Youth, and so on, but it is also the snake that takes immortality away from man. [To reiterate] It is said that it couples with women. Persian and rabbinical traditions claim that menstruation is due to the first woman's intercourse with the snake.
Is this true (i.e., do Persian and rabbinic traditions actually say this)?
This question is (probably) unanswerable in the affirmative without quoting a religious source. Hence, if rabbinic tradition does say as much, I would prefer an answer that provides a (brief) summary of the reasoning that led to such a claim.
Since I'm citing a print text, some bibliographic data:
My book is the 1st Vintage Ed., May 2011, ISBN 978-0-307-27778-7, with translation done by Borde and Malovany-Chevallier. I am told other translations can differ dramatically in wording and content. p.169 lies a few pages in to Part III, Ch. 1 ("Myths").