I’d like a straight answer on the connection between menstruation and the moon. There IS a connection. Without trying and without thinking about it, my monthly menstrual cycle begins on the full moon nearly every month. I can’t find any real scientific answer about why this happens - I am not satisfied with the mystical connection answers. And, according to one source, the gravity affected on the body’s water by the moon is not enough to cause the onset of menstruation. What is it then?!?!?!
Coincidence. It happens that your cycle and the lunar cycle are approximately the same. From this essay about lunar effects on human behaviour:
AFTERWORD: After this essay appeared, I received some angry letters from women berating me for not mentioning the menstrual cycle. They seemed to think this showed a deep antifeminist prejudice in me. In every case, I answered by saying that I had never dreamed anyone would think there was a connection. As nearly as I can make out from my knowledge of women, the menstrual cycle is often irregular, sometimes extremely so. Even the average period is not exactly equal to the Lunar cycle, and it’s certainly not the case that the onset of menstruation invariably comes at the full Moon or at any other phase. Rather, on any given week, regardless of the phase of the Moon, roughly one quarter of the women of the appropriate age are menstruating. Why, then, is the menstrual period nearly equal to the Lunar cycle? Might there not be such a thing as coincidence? (The menstrual periods of other primates are widely removed from the Lunar cycle, by the way.)
It is easy to ascribe such timings to coincidence but it is also wrong to do so. The fact that my menstrual cycle coincides EXACTLY with the full moon is NOT a coincidence. It happens too regularly to be a coincidence and it is too widespread a phenomenon throughout history.
On the essay, the main point: “Our complex minds might still sway rhythmically in the half-day and fourteen-day tidal cycles that affected our ancestors so many millions of years ago.”
… well, it’s just totally lacking in any solid explanation. I don’t know who those feminists are that laid into the author but they really had no reason to… the author presented no convincing arguments. By convincing, I mean scientific, which, I suppose, may or may not be convincing to certain people.
In any case, it is easy to call the timing between the lunar and menstrual cycles coincidental, but it is also inaccurate and leads no further to a true explanation.
It’s a coincidence that YOUR cycle matches. Others do not necessarily match, and if some do and some don’t, it is a good argument that the ones that do are coincidental. If there is some mechanism at work that causes you to match the moon’s cycle precisely, why does it not operate similarly with other women? There is a wide variation in the length of menstrual periods in different individuals, for example: my sister’s cycle varied from six to eight weeks (an extreme case). The average is much shorter than that, but there is no mechanism that causes all women to have the same cycle. Some of them may have a cycle exactly the same length as the lunar cycle, but most will not.
What evidence?
Cite?
Why? Coincidences do exist, it’s not wrong to point them out. The odds are overwhelmingly against you winning the powerball lottery, yet every week, someone somewhere does win.
Oh. You say that with such authority, would it be presumptuous to ask what evidence you’ve uncovered so far?
(setting aside the history thing, which really isn’t verifiable…) Womens’ menstrual cycles fall everywhere between 26 and 31 days on average, some much longer than that. Out of the mass of women on earth, given such a small window for variation some of them must have a period that concidentally falls exactly on the full moon. And some by a day’s offset every month, and so on, and so on.
This article discusses the cycles of other primates.
There’s no reason to suspect that humans have been singled out for synchronization with the moon, or that even specific individuals have. (BTW I’m sure that if you were taking birth control pills you would know that they regulate your cycle and it could be regulated, by coincidence, to be the same as the lunar cycle, but you didn’t mention you were so I’m assuming not.)
Nature is full of coincidences. We have lunar eclipses because the moon’s size as seen from the Earth is nearly exactly the same size as that of the sun. There is no physics that says it must be so, and Earth is somewhat unique in that regard.
In contrast, one side of the moon always faces Earth; this is not a coincidence and the physics of this orientation have been understood for a long time. But it required scientific evidence to demonstrate it was not a coincidence, rather than the other way around.
Every once in a while, my cycle with sync with the moon. It’s neat when it does, in some romantically pagan way.
Then three or four months later, I’m out of sync with the moon, and that whole moon-feminine-godess-primal-one-with-nature sort of falls to the wayside. Until the next time it happens, maybe a year and a half later.
28 days, 28 days, it sure seems like it should be connected. But it doesn’t seem to be.
I once had a friend who was an intelligent man, and yet he honestly believed all women menstruated at the same time every month.
Come on, if that were so, don’t you think it would be scheduled into public life? 
with = will
godess = goddess
Do not post after consuming almost an entire bottle of “Naked Grape” by oneself. On a Friday night.
Anecdotal evidence time:
My mother’s menstrual cycle never coincided with the full moon. Before my cycles were completely borked by the contraceptive implant I’m on, neither did mine. I was offset by anywhere between three days and a week. Of my group of approximately 1 dozen girlfriends at school, about three or four of us ‘moon cycles’ IIRC. The rest were scattered everywhere over the map (at least to start with. After spending nearly five years spending almost every day and most weekends together, some of us seemed like we started to synch a bit, but that’s another thread).
Your answer? What everyone else has said - your cycle happens to be a coincidence. Some girls have a cycle that rides on the full moon, regular as clockwork, the rest of us fall anywhere in between.
Before I was spayed, my cycles were a bit longer than four weeks, or even the 29 and some odd fraction days of a lunar cycle, without outside interference. I noticed that my cycle would start on the full monn, for instance, in May, and by September I’d be starting my cycle on the moon’s last quarter. When I was on the Pill, of course, I had a 28 day cycle, and after my pregnancies, my cycle fluctuated widely. I’ve heard of women who had cycles as regular as clockwork…but the cycles were all of varying lengths. Some women had cycles as short as every three weeks, and others would go half a year without menstruating, or being pregnant.
Simply put, if a particular woman’s cycle coincides with the phases of the Earth’s Moon, then it’s a coincidence, no matter how much one would like to believe otherwise.
First you say “nearly” then you say “exactly”. It can’t be both. Sometimes it clearly is off (by a few days or more, I presume). Why is that? Moon phases don’t change, they’re absolute, currently, and it will be many millions of years before it is likely to change. But your cycle is sometimes irregular.
Therefore, there is no connection.
For 30 years my cycles have been regular as clockwork - on a 32 day cycle. So I never match a lunar cycle. For 30 years.
smartie, your case is just coincidence.
As CookingWithGas has pointed out, the month-long cycle of H. sapiens’s menstrual cycle is unique. If the moon dictated menstruation in humans, why would it not do so in the rest of the animal kingdom? That alone proves that it’s coincidence; that we just chose 29 days in the office pool.
smartie, if your periods do match the full moon appearance either exactly or approximately, you couldn’t be questioned on it if you kept a written record for, say, two or three years. The calendar will have the moon phases on it and you can mark on it the period onset. Without a record you are likely to get a distorted view. You notice and remember when the onset coincides with the full moon and not otherwise.
Also chances are even though nearly absolute regularity is the case now it won’t always be so. As others have noted, things can change.
Assume there are approximately 1.5 billion women menstruating in the world. That means 4 million every day on average. This occurs at all phases of the moon. So even if period cycles were tied to the moon, the full moon wouldn’t be an especially favored time since all other phases would yield the same incidence of the onset of menstruation on average.
The moon revolves around the Earth, on average, every 27 1/3- days–it goes through the complete zodiacal cycle each time. However, the time between full moons is on average 29 1/2+ days, as others have pointed out, because of the earth/moon revolution around the sun.
(The length of the year divided by the full moon cycle is 365.256 / 29.531 = 12.369, so there are a little over 12 moon cycles per year. We lose a cycle because of the revolution of the earth/moon around the sun, which is why 365.256 / 27.322 is 13.369, exactly one more.)
It’s been a long time since I took a logic class, but every once in a while I poke my head into GD. Not even poke, but just turn down the lights in my room and pull back the curtain just enough to see in. From what I’ve learned over there, this seems like an amost perfect example of confirmation bias, without hard data anyways. When it happens, she notices it, and decides it most not be coincidence. It it doesn’t happen one month either it’s not noticed or excused as an anomoly.
Okay dudes… okay… it is just coincidence that i menstruate on the full moon. okay. my little coincidence. let’s examine what other people have to say on this:
“Women’s periods have been tied to the moon and the lunar cycle for literally thousands of years. Before modern science came along to explain that a woman menstruates because of her changing hormones, it was generally accepted that a woman’s periods followed the lunar cycle.” http://www.epigee.org/menstruation_lunar_fertility.html
“It has been shown that calendar consciousness developed first in women because their natural body rhythms corresponded to observations of the moon. Chinese women established a lunar calendar 3000 years ago. Mayan women understood the great Maya calendar was based on menstrual cycles. Romans called the calculation of time menstruation, meaning knowledge of the menses. In Gaelic, menstruation and calendar are the same word.” http://www.fwhc.org/health/moon.htm
It is thought that perhaps moonlight had something to do with these cycles and since we’re less exposed today to moonlight, women are less in synch with the moon. Of course, there is or was no way every woman is always going to be in synch with the moon. It won’t happen. Too many variables. And what “we” are all agreeing on is that there can be no connection between the moon and the body? Even for some women particularly prone to certain things? do i hear a yesyes?
I think it’s safe to say there is no demostrable connection, nor a plausible mechanism for a connection. Absent new evidence, we have to conclude: the average length of the human menstrual cycle and the length of the lunar cycle do not influence each other, and where they are the same in individuals, it is coincidental.
.
Sorry.