Another Period Question...

[Aggie]

Why is it (if it's true) that women's cycles start to sychronize when they are around other women?

I went to an all girl's school and every month it seemed like one half of the school had their period at the beginning of the month and the rest of us had it towards the end. And every summer when I would go visit my dad and step mother, my cycle would change and I would end up having it the same time as my step mom.

Is there a reason for all this madness? Why would anyone want a bunch of women to have PMS at the same time?

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[Jennitalia]

lol, i just wondered about that in my period thread, Aggie. I've always been fascinated by that. It happened to me and a couple of my roommates in college.

There's nothing worse than putting a bunch of girls on the rag in the same room - PMS overload!

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[ChrisTheCop]

One theory is that the phenomenon dates back to caveman/tribal times, when a man would take on many mates in a short period of time in order to propogate the species. It would be necessary for the women in the tribe to be fertile at the same time, and nature provided the answer. This doesnt answer your qyestion as to HOW it happens, but hey, I'm trying here. On a related note, recent studies show that women who hang out with men more than women have shorter less painful cycles.

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[Aggie]

great tookies think alike jen!

and chris, you're scaring me a little with all the period talk. but hey, you ARE studying for jeopardy so i guess i should expect this from now on.

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[TooCute]

It is because of pheromones, and the same thing happens in lot sof other animals too. For example, if you keep female mice in two separate cages, they own't go into heat at the same time. If you connect them so that they share air, they will. Some pheromones can travel through the air.

One theory is that menstrual synchrony evolved in groups of humans where there was one dominant male. If only one female ovulated at a given time, the male would mate with her, and then when another was ovulating he'd mate with her, and so on, and none of the females would get the full attention (and resources like food he hunted) of the male. The other, non-dominant males, wouldn't not bother to help her because the offspring wasn't theirs.

But if all the women ovulate at the same time, then that means that the dominant male would have a much harder time mating with all of them. Some of them would be able to mate with males other than the dominant male, and therefore benefit from having the full attentions of their mate (which in turn means that their offspring would be more likely to survive).

Lots of other animals display breeding synchrony, for example birds that live outside of the tropics do, for a similar reason to what is postulated for humans - there's only a certain time of year they can breed where there will be tons of food for their offspring, and if all the males are there looking for females at that time of year (because that's the time of year where they are all fertile), the females can then choose whichever male they want to be the father of their offspring. Birds that live at the equator don't display as much breeding synchrony, probably because food is available year round.

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[The Chairman]

It is because of pheromones.....


Too Cute posted the definitive, authoritative, end of discussion, answer.

End of discussion?

I wonder.






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[HordeKing1]

The phenonenom is called synchronized menstuation.

There have been several theories advanced but the prevailing theory, is, as pointed out by Too Cute based on Pheremones.

Women's sweat contains 2 pheremones, one of which lengthens the cycle and one of which shortens it. (Men's sweat also contains pheremones of a different type).

When the pheremones from a group of women living together mix and mingle over time, some women's cycle lengthen, some shorten until many of them are in synchronicity. It takes about 6 months to fully change.

Men's pheremones also affect women's periods. Women who hang out with men typically develop shorter and more regular periods.

An interesting fact (but hard to explain from an evolutionary perspective) is that most sex takes place at around the time of menstuation when women are least fertile. Ovulation is the time of greatest fertility, but more sex occurs when women are at their least fertile. Perhaps this is due to the phermone receptors in men. They respond to the pheremones produced by menstuation and know they have a better chance of having sex. (blood is a lubricant and turns on many women). Again this is hard to understand from an evolutionary perspective.

Aya, can you shed some additional light on this?





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[Aggie]

...that most sex takes place at around the time of menstuation when women are least fertile...


I'm always horny right before or during my period. That's always seemed strange to me, but it's like clockwork.

Thanks for the info guys, I didn't even know if it was a real thing.

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[TooCute]

An interesting fact (but hard to explain from an evolutionary perspective) is that most sex takes place at around the time of menstuation when women are least fertile. Ovulation is the time of greatest fertility, but more sex occurs when women are at their least fertile. Perhaps this is due to the phermone receptors in men. They respond to the pheremones produced by menstuation and know they have a better chance of having sex. (blood is a lubricant and turns on many women). Again this is hard to understand from an evolutionary perspective.


I was under the impression that womens' libidos are at their highest when they are ovulating. I know that during menstruation itself, libido can go up, but nowhere near how you feel when ovulating (actually I personally rarely feel like having sex when I've got my period at all). I know that males can detect pheromones present in womens' sweat when they're ovulating, and nevermind blood being a lubricant; the vaginal secretions are heavier and wetter during ovulation so that doesn't seem like it'd play so much of a factor.

If this is in fact true (I have a hard time believing it, but I have a hard time believing MANY things about human sexuality so it wouldn't surprise me if I didn't already know that womens' libidos are supposedly highest during ovulation) then the only thing that I can think of is that women who like to have sex during their periods like to have sex with men who they do not view as potentially good providers in the future for the express purpose of not becoming pregnant.

I don't know. I wonder if a poll of the messageboard would show people having more sex when the chick is or is not having her period (forget libido, we're just talking straight up the amount of sex, right?)

Personally: I have more sex when I'm not having my period than when I do. I can't help but thing about the laundry I'm going to have to do when we're done and the amount of clean up of my own body there will be afterwards and it just kills the mood for me.

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[silera]

On a related note, recent studies show that women who hang out with men more than women have shorter less painful cycles.

No wonder dykes are so cranky.


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[Arienette]

I wonder if a poll of the messageboard would show people having more sex when the chick is or is not having her period (forget libido, we're just talking straight up the amount of sex, right?)i'm not sure whether this was an invitation or not, but...

for my part, i have pretty much the same amount of sex during my period as i do when i'm not having it (well, not the same amount really, since it's only about 1/4 of the time. i guess it would be more accurate to say at the same rate). except for the couple of hours where my cramps are the most painful and before the pills kick in, i have no problem with having sex while i'm having my period. and even though it wasn't really the question, my libido (apart, again, from the times when my cramps are really bad) is pretty much the same throughout the month.

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