Menstrual Cycle woo

[pmckean]

I was discussing the female period with my partner (as you do), and she mentioned that her menstrual cycle tended to synchronise with other women she would spend long periods of time with.

When she lived at home, this was her sisters. When she moved away, it was the two women she shared a flat with. In her words, it would take only '2 or 3 cycles' before they were evenly matched up. Now, she reckons it even occurs with the women she works with, though not to the day.

I've heard this before, obviously, but not thought much about it. I asked her why she believes this happens, and she suggested it had a lunar basis.

Now, that's patently nonsense, but is there a hormonal effect here, or does it happen at all?

[scratchy]

Ive also heard this before, but i didnt really buy in to it. Mainly because the creature who told about it was a major dimwit and totaly absorbed by bizarre notions about reality. But i cant honestly say im convinced that its not true, and im very interrested to hear some scientific thoughts about it.

[TTLer]

Attn pmckean:

You're barking up the wrong tree by posting here, absolutely.

This is not a forum to ask biological questions about your girlfriend's vagina.

Indeed however, all the answers to your questions are available on Wikipedia:

http://en.wikipedia.org/wiki/Menstruation
http://en.wikipedia.org/wiki/Menstrual_cycle
http://en.wikipedia.org/wiki/Menstrual_cycle#Hormonal_control

After educating yourself, if you still feel there's an issue to be discussed among fellow skeptics, bring it on. Otherwise, please don't clutter up our forum.

[fuelair]

Attn pmckean:

You're barking up the wrong tree by posting here, absolutely.

Indeed, all the answers to your questions are available on Wikipedia:

http://en.wikipedia.org/wiki/Menstruation
http://en.wikipedia.org/wiki/Menstrual_cycle
http://en.wikipedia.org/wiki/Menstrual_cycle#Hormonal_control

After educating yourself, if you still feel there's an issue to be discussed among fellow skeptics, bring it on. Otherwise, please don't clutter up our forum.If you do not think you should have added a friendly smiley to this, politeness goes further than snarky for the most part. On our forum.:cool:

[SezMe]

That's unduly harsh. :( I can't count the number of times that posters have been sent off to the Wiki to get relevant information. That does not mean that they were "cluttering up" the threads.

Oh, and BTW, a little humility might be called for before a poster who has been here for less than a month and has 20 posts describes "our" forum to someone who has been registered for over three years and has nearly 10 times the number of posts you do.

ETA: fuelair wins the quick draw.

[Jackalgirl]

After educating yourself, if you still feel there's an issue to be discussed among fellow skeptics, bring it on. Otherwise, please don't clutter up our forum.

Excuse me? Aren't you a bit too shiney-new to be taking it upon yourself to speak for the Forum?

To the OP: I've heard of this, but I haven't experienced it. I lived in a very cramped berthing compartment with 17 other women for 6 months and as far as I could tell (from the contents of the trash we had to take out on a daily basis) our periods never synched up.

Edited to add: um, what fuelair and SezMe said. ; )

[ponderingturtle]

That's unduly harsh. :( I can't count the number of times that posters have been sent off to the Wiki to get relevant information. That does not mean that they were "cluttering up" the threads.

Oh, and BTW, a little humility might be called for before a poster who has been here for less than a month and has 20 posts describes "our" forum to someone who has been registered for over three years and has nearly 10 times the number of posts you do.

ETA: fuelair wins the quick draw.

As an addition to this, I would not consider Wikipedia to be much of a source on something like this, though it can be a place to find better sources.

[fuelair]

http://www.collegian.psu.edu/archive/2002/10/10-08-02tdc/10-08-02dscihealth-03.asp supports but notes counters too (it has been theoretically observed in close groups but the data is not sufficient so far).

[The Atheist]

Attn pmckean:

You're barking up the wrong tree by posting here, absolutely.

Indeed, all the answers to your questions are available on Wikipedia:

http://en.wikipedia.org/wiki/Menstruation
http://en.wikipedia.org/wiki/Menstrual_cycle
http://en.wikipedia.org/wiki/Menstrual_cycle#Hormonal_control

After educating yourself, if you still feel there's an issue to be discussed among fellow skeptics, bring it on. Otherwise, please don't clutter up our forum.

Excuse me for the third or fourth time, but who the hell are you and wtf do you think you're doing.

Every post of yours I've yet seen is almost identical to the crap I've just quoted. As others have so eloquently noted, unless you've bought the forum off JREF recently, you are talking through a hole in your head and it most certainly isn't welcome.

I've said to you before; if you want to raise a subject for discussion - start a thread. If you have no relevant comment to add, stay out.

You have definitely picked the wrong place to bring that attitude to.

[The Atheist]

I was discussing the female period with my partner (as you do), and she mentioned that her menstrual cycle tended to synchronise with other women she would spend long periods of time with.

When she lived at home, this was her sisters. When she moved away, it was the two women she shared a flat with. In her words, it would take only '2 or 3 cycles' before they were evenly matched up. Now, she reckons it even occurs with the women she works with, though not to the day.

I've heard this before, obviously, but not thought much about it. I asked her why she believes this happens, and she suggested it had a lunar basis.

Now, that's patently nonsense, but is there a hormonal effect here, or does it happen at all?

This is one which might be easily dispensed with. Most women of child-bearing age take the contraceptive pill. Other than a couple of days either side, periods are as regular as clockwork and essentially immovable without changing the pill dates.

She will only be able to make a case if she and her buddies/co-workers are all not using contraceptive pills.

I have no idea on the chances of it being possible in women not on the pill, but I guess some kind of pheromone-based change is within the bounds of possibility. Interesting question.

Bizarre coincidence, I was reading about the positive effects of yoga on PMS (http://www.nzherald.co.nz/section/story.cfm?c_id=204&objectid=10452834)just before coming to the forum.

[TTLer]

TheAtheist, this is a skeptic forum. If you're not a skeptic, please go post your musings on a paranormal lacky site.

[PogoPedant]

This is a skeptic forum. If you're not a true skeptic, go home, get away from here.

You haven't been hugged enough, have you?

:rub:

There, there.

[Professor Yaffle]

This is purely anecdotal, but when I was a student and sharing the house with other people, our (the females among us) cycles did usually synchronise quite well. We would start off all over the place but towards the end of the academic year, we would be quite close. Mine didn't alter very much - my cycle becoming very slightly shorter if anything, but some of the girls with shorter cycles had a more appreciable difference (suspected pregnancies were common as their periods were always later than they expected). The usual explanation I heard was nothing to do with phases of the moon, but to do with pheromones.

I just found this on the Straight Dope - http://www.straightdope.com/classics/a2_306.html

Apparently I am a "menstrual pacesetter".

But a different straight dope page http://www.straightdope.com/columns/021220.html suggest that scientific opinion on the matter is divided. This is the most recent research on it that i could find - http://transactionpub.metapress.com/app/home/contribution.asp?referrer=parent&backto=issue,6,8;journal,2,21;linkingpublicationre sults,1:112435,1

[pmckean]

Well, TTLer, it's a forum, where people debate things.

As a matter of fact, I had done a little research on Wikipedia and noted that there was no conclusive information on whether synchronised mentrual cycles exist - yet many people believe in them.

That would seem like something worth talking about, then.

Is this subject taboo for skeptical discussion? I refrained from using scatalogical terminology, and assumed that we're all adults.

Anyway, back to the topic.

Wikipedia mentions the McClintock effect, described in 1971, however there's been criticism of this research that suggests that synchronised menstruation may have no statistical basis.

We'd have to ask ourselves;

a) Is it happening?
b) if it IS, then why did such a biological trait evolve?

I'm guessing that this could have developed to prevent men from sleeping with other females during their regular partner's cycle - if all of them were similarly disadvantaged, males would have nowhere to turn. This assumes that there is an evolutionary advantage to monogamy, which I haven't researched. I can't see that there is, for men.

Anyway, complete speculation.

[TTLer]

Excellent stuff, pmckean, now there's some grist for good discussion!

I have some data to contribute, honestly:

For 2 years, I lived in a house with 3 other women, all lesbians. It was no secret in the house when they all experienced their periods at the same time.

I can attest that the synchronous female period is real.

[pmckean]

OK, TTLer, this is where I get to be a little snarky back.

The anecdotel evidence of three women isn't quite enough for you to positively attest that the synchronous female period is real. The sample is too small, and the potental margin of error too great.

I'm not saying that it isn't real - I'm neutral, at the moment.

For instance, if that was a study you could also conclude (from your post) that 100% of females are lesbians!

[pmckean]

http://www.collegian.psu.edu/archive/2002/10/10-08-02tdc/10-08-02dscihealth-03.asp supports but notes counters too (it has been theoretically observed in close groups but the data is not sufficient so far).

A great link, fuelair. Thanks.

[Oroborus]

Oh man TTler I'm with you on this one. I really hate it when the gnomes point a gun to my head and make me click on all this forum clutter. Drat it all!


If you dont like it, dont read it. I'm sorry you found the entire one thread extra in this forum enough of an irritant to come in and rant about it.

By the way ranting about threads in threads kind of adds to the so called clutter too dontcha think?

[Katana]

Excellent stuff, pmckean, now there's some grist for good discussion!

I have some data to contribute, honestly:

For 2 years, I lived in a house with 3 other women, all lesbians. It was no secret in the house when they all experienced their periods at the same time.

I can attest that the synchronous female period is real.


Quite the little hypocrite, aren't you?

You malign others for not being "true" skeptics and then throw up this anecdote as evidence?

Perhaps it is you who is not in the right forum.

A quick search revealed quite a few studies. A few abstract highlights:

Polish study showing no synchrony. (http://transactionpub.metapress.com/app/home/contribution.asp?referrer=parent&backto=issue,5,8;journal,2,21;linkingpublicationre sults,1:112435,1)

Chinese study showing no synchrony. (http://transactionpub.metapress.com/app/home/contribution.asp?referrer=parent&backto=issue,6,8;journal,2,21;linkingpublicationre sults,1:112435,1)

Review of 8 studies investigating theory of pheromones synchronizing menses that cast some doubt. (http://transactionpub.metapress.com/app/home/contribution.asp?referrer=parent&backto=issue,7,8;journal,2,21;linkingpublicationre sults,1:112435,1)

Small study from 1990 out of Israel showing synchrony in lesbian couples. (http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=1438642&dopt=Citation)

Looking a bit further, it would appear that the most recent studies fail to show that women synchronize their menses while older (15-20+ years or older) were more likely to do so. There also appeared to be some flaws in the earlier studies. See here for an interesting review of some of these issues (http://66.102.1.104/scholar?hl=en&lr=&client=firefox-a&q=cache:VJ6Cfp5nwkAJ:mentor.lscf.ucsb.edu/course/winter/psyc594jr/Human%2520Mating/other%2520pdf%2520readings/Wison.pdf+menstrual+synchronize).

Having said that, the idea is not so implausible. We know that times of extreme stress can alter, even suspend the menstrual cycle. If a group or population of women experienced such conditions together and then got through the experience together, might they not resume their menses together? I realize that that's different than actually synchronizing by simple proximity, but it is one way that cycles could come into line. As for a hormonal, or pheromone, effect, it seems less likely.

So, because, as with many subjects discussed here, menstrual synchrony is a phenomenon often accepted by the public that the scientific literature may not support, it is most certainly worthy of discussion.

People who do not think so are free to ignore the thread or find themselves another forum where they may find topics more worthy of their great insight and intellect.

[mumchup]

I've been hearing about this for years and been a part of groups with "synchronised periods".
But the best explanation for it, IMHO, is just selective noticing. A few reasons for this:
All women don't have periods lasting exactly 28 days from start to start (or whatever it's supposed to be). They might have longer cycles, longer periods, start late, start early, and such. The bit Katana dug up about it supposedly happening more often to older women would support this because as you get older your period is likely to become more variable.
If our periods are all just a little bit variable from each other and from month to month, then it makes sense that occasionally they would occur at the same time, for a month or two. (or more)
As skeptics, we are all aware of the fact that people often only remember the hits and forget the misses. So if I mention that I got my period 2 weeks after my roomate, she's not going to remember that; but if it's 4 days after she got hers: We must have synchronised periods. Similarly, there's a fairly large part of the month that could be counted as being close enough, like feeling premenstrual, being menstrual, or having just ended being menstrual.
I'm not counting out that there could really be an effect, but it seems to me that it would be a little easier to pin down an answer if there were.

[mumchup]

And the next time someone complains about the people on this forum, maybe I'll send them to this thread to prove them wrong.

[casebro]

I would think you need a smallish group. In the randomness of a large group, there would be no sole 'peak' to move towards.

Do girls start right in step with their Moms?

I would suspect the evolutionary advantage would be within a family- it would prevent Dad from seeking his daughters during Mom's bad days.

Herd fertility? More babies born at the same time, to promote survivability?

When I first heard the theory, I thought "AHA! That explains all those screaming matches between my mom and my two sisters- they all had PMS at the same time!". So perhaps the evolutionary advantage would be to break up family groups of women- all that PMS would drive some out of the nest?

Next thought- Is there an evolutionary advantage to PMS? It's common enough to require some kind of advantage- drive the current mate away, to vary the genes? Drive competing women away?

[mumchup]

Sound ideas, casebro. I seem to remember something about baboons along those lines, that only the dominant female ovulates.
But I am far from convinced that it occurs at all. The evidence is way to thin for me.

[nails3jesus0]

i heard about the pharamones subconciously making women sync up. Ive never really thought about it too much because i havent ever experienced this sort of thing, i figured it was something that happens to some groups of women but not all.

[ponderingturtle]

Sound ideas, casebro. I seem to remember something about baboons along those lines, that only the dominant female ovulates.
But I am far from convinced that it occurs at all. The evidence is way to thin for me.

The problem with that idea is that humans don't seem to have a breeding season, so I am not at all sure you would get enough simultanious pregnancies in the size groups that existed to be of any benifit.

[kellyb]

The problem with that idea is that humans don't seem to have a breeding season, so I am not at all sure you would get enough simultanious pregnancies in the size groups that existed to be of any benifit.

I just read this the other day, as it was one of the NS headline articles, but I don't think baboons have a set-in-stone breeding season, either:

http://www.newscientist.com/article/mg19526135.400-primates-on-the-pill.html

Primatologist Patricia Whitten of Emory University in Atlanta, Georgia, thinks that it might benefit the baboons, which are able to breed year round, not to conceive in the plum season, as this is the rainiest time of year, when disease is most likely.

But they apparently might use plums as contraceptives at certain times.

Anecdotally, I'm pretty sure I've experienced the period-syncing thing, but it also could have been a memory-bias phenomenon.

[ponderingturtle]

I just read this the other day, as it was one of the NS headline articles, but I don't think baboons have a set-in-stone breeding season, either:

http://www.newscientist.com/article/mg19526135.400-primates-on-the-pill.html

SOrry I was being unspecific I was thinking of Casebro's idea about large numbers of children timed to be born at the same time to lower loss rates to predetors.

As for only dominants being fertile that makes sense in some species I guess.



But they apparently might use plums as contraceptives at certain times.


Interesting.

[Miss Anthrope]

TheAtheist, this is a skeptic forum. If you're not a skeptic, please go post your musings on a paranormal lacky site.

Correction. This is the Science, Medicine and Technology section of a skeptical forum. So someone being "skeptical" or asking questions about this is doing exactly what is normal in this section of the forum.

As a person who adores this forum and it's members, I will politely ask you to please be civil. This is one of the most civil forums on the internet. Mockery is done most often with a smile around here. It would seem you might be used to the more hostile waters of other places, but it's not the case with JREF. We have our moments, but it's nothing like most other boards.

It would serve you well to remain neutral until you are familiar with the posters and topics that are the norm around here.

[pmckean]

Ooh, I just noticed my private message from TTLer, sent this morning:


Go Away

You are being collectively ignored by the entire 13,000 JREF forum members.


What a pleasant new member of the forum.

Thanks to those who stood up for free speech and reasonable discussion in this thread.

[thaiboxerken]

I'm thinking TTLer might be a woo who is simply playing a charicature of a skeptic.

[Miss Anthrope]

I'm thinking TTLer might be a woo who is simply playing a charicature of a skeptic.

The thought occurred to me as well. Time will tell.

[pmckean]

I'm thinking TTLer might be a woo who is simply playing a charicature of a skeptic.


It's a rather devastating critique if he's serious. ;)

[LibraryLady]

It's a rather devastating critique if he's serious. ;)

No, I think it'd be a devastating attack if it were accurate. If this is what he's attempting, I don't think he's being successful.

[Rob Lister]

I'm thinking TTLer might be a woo who is simply playing a charicature of a skeptic.

The word I was think of started with a T

Perhaps he's having his period.

[The Atheist]

TheAtheist, this is a skeptic forum. If you're not a skeptic, please go post your musings on a paranormal lacky site.

I'm thinking TTLer might be a woo who is simply playing a charicature of a skeptic.

I agree as well. The first five posts I've seen by this cute new addition to the membership has been almost identical in its import. I'm waiting for it to make an intelligible comment. Hope springs eternal.

It has all the hallmarks of this business of YECs demanding "scepticism" of evolutionary theory.

Classic example of TTLer not using critical techniques in his/her own thinking is the classing me as a theist. (n.b. the edit data on the above post original above)

How quaint!

[The Atheist]

Ooh, I just noticed my private message from TTLer, sent this morning:

What a pleasant new member of the forum.

Thanks to those who stood up for free speech and reasonable discussion in this thread.

And maybe a sock-puppet.

I've seen this style plus PMs before. Must go check back some old threads when I have time, because I'll be surprised if this is his first visit here.

**You are able to report PMs, you know, pmckean, and that's a fairly abusive kind of thing to PM. Especially from a "real skeptic" who posted Wiki links to end a discussion!

:dl:

[Gilmar]

Women's Synchronized Cycles - is that, like, a new Olympic event?

[SezMe]

In addition to the bad attitude, I thought Katana really nailed this fiercely true blue skeptic with this.

Quite the little hypocrite, aren't you?

You malign others for not being "true" skeptics and then throw up this anecdote as evidence?

He has one relevant experience and, based on that, declares an end to the controversy. Damn, where's that dog?

[DmKrispin]

Okay, back to the period thing. As far as I know, girls do not start in rhythm with their mothers, sisters, or other female household members. When a girl first starts her period, it is usually irregular. I have never "synchronized" or heard of anyone who did (I know that's anecdotal, but my mom did grow up with six sisters). Menstrual cycles vary widely among women; the cycle is not every 28 days for every woman, neither is the duration or intensity the same for every woman. Even women taking the pill don't all start the cycle of pills at the same time. Often after childbirth (and/or breastfeeding) a woman's period will be irregular as her body "gets back to normal". Also, stress, extremely low weight, and other factors can mess with a woman's cycle. With menstrual cycles being so varied, I think that true synchronicity (not coincidental sync) would be quite difficult to achieve, if it's even possible at all.

[Miss Anthrope]

I've synchronized with a female housemate, and I've not synchronized. My anecdotes taught me it's probably just coincidental, or possibly hyper awareness as suggested earlier.

[dakotajudo]

I'd heard of menstrual cycle synchrony back when I took undergrad physiology, and maybe even repeated it, back when I taught physiology labs. But I've never really considered it critically (so shut up, TTLer, this was a good thread for me).

Anyway, I did a pubmed, and the first citation suggest that synchrony may depend on hygiene - see http://www.ingentaconnect.com/content/ffp/jfp/2007/00000033/00000002/art00015 .

Well, if it is pheromonal, that makes sense. There seem to be pheromones in sweat that active regions fo the hypothalamus.

As for an evolutionary basis - maybe there isn't one - maybe it's simply a side effect of the higher levels of hormones needed to trigger some of the physiological processes, or bi-products of their breakdown.

[fuelair]

And maybe a sock-puppet.

I've seen this style plus PMs before. Must go check back some old threads when I have time, because I'll be surprised if this is his first visit here.

**You are able to report PMs, you know, pmckean, and that's a fairly abusive kind of thing to PM. Especially from a "real skeptic" who posted Wiki links to end a discussion!

:dl:

Not to mention that the Wiki links did not address the OP point/question - just general info on major topic.

[Hydrogen Cyanide]

Also, not every woman has the exact cycle. My natural cycle was actually about 6 weeks, and during my fairly few years on birth control pills it turned into 8 weeks (and then later during my 40s it went to 10 weeks, then 12 weeks, then 6 months... and I thought I was post-menopausal except a few months ago I had a cycle after 3 years!). For some women it can be as short as 3 weeks, or 5.5 weeks.

So if a set of women with certain various different cycle frequencies live together, the times that the cycles coincide would be more memorable, than other times. The extraordinary events stick in your head more than the mundane events.

[articulett]

My 2 sisters and I synched... my college dorm mates synched and me and a female roommate synched. In fact, I realized she was pregnant probably at around the same time she did-- excess tampons in the box for me.

I've also heard that women in relationships (with men) are more regular...

My experience fits the studies I've read on both counts... but maybe I'm suggestible... or just a sample of one.

[The Atheist]

As far as I know, girls do not start in rhythm with their mothers, sisters, or other female household members.

That could well be used as proof of god [being male].

[casebro]

Another anecdote: My sister was well into menopause, thought she was all done. When her daughter moved back in for several months. She started regular cycles again.

I'd pick pheromones as the signaling system. The change in smell is obvious. Even guys know that women smell different at that time of the month. It's the original use of the word "funky".

[king catfish]

Nevermind. Better said by others before me. :)

[Hydrogen Cyanide]

My 2 sisters and I synched... ....

I never synched with my sisters. But then, again... I seldom synch with them on anything. At our last family wedding, I was forced by them (and my hubby) into "sister time". I watched them put on make up and nail polish, while avoiding their attempts to apply the stuff to me.

[articulett]

I never synched with my sisters. But then, again... I seldom synch with them on anything. At our last family wedding, I was forced by them (and my hubby) into "sister time". I watched them put on make up and nail polish, while avoiding their attempts to apply the stuff to me.

Me neither... I tell myself they synched with me-- I'm alpha :D One sister is an evangelical Christian and another is a New Age yoga nut. My brother is a conservative Catholic. I guess I got all the brains as well as pheromone dominance.

[Juliette]

[QUOTE=Hydrogen Cyanide;2791200]I never synched with my sisters. But then, again... I seldom synch with them on anything.

It's interesting, it seems that I continue to hear about female siblings, seldom synching on anything. Though I have never synched with my sister in any other way, we had identical menstral cycles.

Though I always questioned why, most anecdotal experiences - work, school, roomates - have seemed for the most part in synch. Not as closely as with my sister, but still synched within a day or two.

Again, questioning why, nothing has ever seemed definitive. What I heard mostly from other women was connected to the (yawn) lunar cycle. So far, the relationship with pheromones makes the most sense to me.

It's always interesting when statistics clearly say one thing, such as in the studies Katana refered to showing no synchronx, yet lifetime anecdotes show something so different. It is probably that my anecdotes have been based on purely selective memory.

Julia

[RSLancastr]

I was discussing the female period with my partner (as you do), and she mentioned that her menstrual cycle tended to synchronise with other women she would spend long periods of time with.

Oh, that's bush-league (so to speak) menstrual woo.

Do some Googling on "wicca" and "menses," and you'll see some high-grade woo.

[mumchup]

Oh, that's bush-league (so to speak) menstrual woo.

Do some Googling on "wicca" and "menses," and you'll see some high-grade woo.

Something tells me that if I follow your google advice, I'll be very sorry :)