What's the link between the moon and menstruation?

What's the connection between the human menstrual cycle and the moon? Do cycles last exactly one lunar month for a reason, or is it just a coincidence?

It looks like it's coincidence. In Science and the Paranormal (1983), astronomer George O. Abell writes, "The moon's cycle of phases is 29.53 days, while the human female menstrual cycle averages 28 days (although it varies among women and from time to time with individual women); this is hardly even a good coincidence! The corresponding estrus cycles of some other mammals are 28 days for opossums, 11 days for guinea pigs, 16 to 17 days for sheep, 20 to 22 days for sows, 21 days for cows and mares, 24 to 26 days for macaque monkeys, 37 days for chimpanzees, and only 5 days for rats and mice. One could argue, I suppose, that the human female, being more intelligent and perhaps aware of her environment, adapted to a cycle close to that of the moon, while lower animals did not. But then the 28-day period for the opossum must be a coincidence, and if it is a coincidence for opossums, why not for humans?"

Then again, who knows? People have figured there was a connection between the lunar month and menstruation for as long as women have been getting the monthlies. Moon, month, and menstruation are all related etymologically. No less an authority than Charles Darwin believed that menstruation was linked to the moon's influence on tidal rhythms, a legacy of our origin in the sea. The coincidence between the lunar and menstrual cycles is closer than George Abell would have us believe--studies have found the average menstrual period is 29 days and change. At least some critters' biologies are linked to the lunar cycle; in the lemur, for example, estrus and sex tend to occur around the time of the full moon.

Efforts to turn up similar patterns in humans have had unimpressive results, however. Several researchers over the years have claimed to detect lunar rhythms in menstrual onset and such; others see nothing. Biologist Winnifred Cutler, in a 1980 paper, found that 40 percent of women in a random sample showed "a preponderance of menses onsets in the light half-cycle of the month" (the two weeks centered on the full moon). To me this suggests 60 percent of the women didn't show any coincidence. If there really is a moon-menstruation link, it hasn't been convincingly proven yet.

(no subject)

Called back the camera people.... the gal there says it'll be refunded today.... I certainly hope so. :) I submitted my negative review to C-net, and got a lovely form letter back. I'll call the bank at 3 today, and make sure it's all back to where it needs to be.

edited for content

woke up late this morning, had a memorable dream last night. I was in a prison break and got hold of a machine gun. I was pinned down behind a concrete wall, but was getting some pop-up fire in. I saw my pal Dave was one of the guards, and tossed down my weapon, not wanting to hurt him. I lay down on my face, and put hands on my head. something happened, and we flash forwarded to an escape method... some sort of tunnel built into a soda machine. I was too big to make it through... I made sure Dave got out, and somehow my sweetie and Newt were there, and needed help escaping too. It spun off into some sort of vacation place...some sort of portal that allowed you to travel to a location stored on video. I ran off with my buddies to the Amazon, and then stole the machine so nobody could follow us. It turned out that the movie we hopped into was made in 1999, so we were three years in the past, give or take. I woke up amidst trying to call myself in the then to get myself to flee.

elephant talk - neat! thanks to sweetalyssm for having me look into it. Fascinating stuff.

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newt pic o' the day.. in my amazon box from sweetie.. note ancient birks in the background.

Newt album is here.

story note reference.

Man forced to stay 11 years at Paris airport now won't leave

By Ray Moseley Chicago Tribune

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