Menstrual Cycle woo

[tmackean]

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]

Go Away (to Wikipedia)

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.

 

[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 just before coming to the forum.

 

[TTLer]

Get a Grip(e)

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?



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...nal,2,21;linkingpublicationresults,1:112435,1

 

[tmackean]

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.

 

[tmackean]

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!

 

[tmackean]

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.

Chinese study showing no synchrony.

Review of 8 studies investigating theory of pheromones synchronizing menses that cast some doubt.

Small study from 1990 out of Israel showing synchrony in lesbian couples.

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.

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.