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Do You Believe in Menstrual Synchrony?

If you've ever lived with other women, and none of you were on hormonal birth control, you may have discovered that your cycles slowly began to mimic each others. This is called menstrual synchrony, but many scientists will say that women who live together, menstruate together is hogwash. I've actually experienced this so there's got to be some truth to it.

In 1971, Martha McClintock studied 135 college women. She wrote down the starting date of their periods at three different times during the year. She discovered that women who lived in close-knit groups had their periods an average of 6 to 4 days apart during certain times of the year. It's said to be caused by pheromones, the release of chemical signals that influence behavior and physiology among people. Other studies conducted after this, however, showed no connection between women living together and their cycles synchronizing.

What do you think about menstrual synchrony? Have you ever lived with a woman (sister, mother, roommate) or group of women and noticed that you had your periods about the same time?


Join The Conversation
shafiii shafiii 9 years
i definetlyy do! My mom, sister, and I all cycle at about the same time and my sister has said she use to cycle at the same time as her roommates
animatedpunk animatedpunk 9 years
yeah, definitely happens. It happened on every sports team I was on in highschool. Not to mention with my close friends and sister.
ktownpolarbear ktownpolarbear 9 years
totally. living in an apartment with 5 other girls, it was totally obvious. and it continued even when there were only 3 of us living together.
Allie1506 Allie1506 9 years
totally! my mom and i always had it together... Dad hated that week!
robins robins 9 years
yes i'm a sisters,my mom and me we get it around the same time!!
JaimeLeah526 JaimeLeah526 9 years
This happens to me all the time with different women.
lilxmissxmolly lilxmissxmolly 9 years
i go to an all girls school and its so funny because everyone, i mean everyone in the entire school, is PMSing at the same time. its like i walk in in the morning and no ones talking to each other and everyone's just sitting around pouting haha, and you walk through teh hallways and hear people screaming for tampons. gotta love it! i didnt know people denied this happened...doesnt it happen in like every tribe in africa? where all teh women get together?
ramenpancakes ramenpancakes 9 years
this happens with myself and all the girls in my workplace, we seem to take turns. it's like clockwork. It's kind of nice though that also we're so close, we kind of keep track of eachother so we'll know if something's wrong.
elizabethgracef elizabethgracef 9 years
My sister, best friend, and I are synced up. My sister and I live together and both have terrible PMS, so we try to go to opposite sides of the house.
pink-elephant pink-elephant 9 years
This is true- It's weird, but every month me and all the other girls on my floor in my dorm all cycle together. I remember the first week I arrived it seriously threw my body out of whack!
IslandGirl IslandGirl 9 years
Firm believer in this! I went to an all girls boarding school and this was a frequent occurrence in the dorms!
graylen graylen 9 years
It's certainly true. Happened at home and in college. Also, I read somewhere that it was important to be synchronized way back in history because that way women were pregnant together (which helped with wet nurses, etc). Also, women in Biblical times went to a separate place during their periods... I believe they thought it was related to the moon cycles, but it would make sense if it was just the hormones!
cereal_please cereal_please 9 years
Seriously.. what's not to believe? I definitely believe this is true. My roommate and I got our periods within an hour of each other just the other day. In high school, all my basketball teammates got our periods within a week of each other. I never really got it the same time as my mother, but I probably spend more time with my roommate/teammates than my mother, so I definitely thing "menstrual synchrony" is real.
Marci Marci 9 years
This is so true. It happened in every office I worked in.
kmholland29 kmholland29 9 years
I definitely believe it! My daughter and I start at the same time.
clareberrys clareberrys 9 years
this is definitely true! the benefits of it happening - you can all be bitchy and crampy together! the downside (especially if sharing a bathroom in a dorm) - you will soon run out of tampons~!
Ikandy Ikandy 9 years
freaky but true. we r miraculous creatures...
jgulli3 jgulli3 9 years
This always happens to me, my 2 sisters and mom... my poor father! :-P
msmoney23 msmoney23 9 years
:OY: All those scientists studying were probably all males! They would know!... ;)
anna_muffin anna_muffin 9 years
Hm, I actually do NOT believe this...or maybe my two sisters, my mom, cousin and aunt are just immune ;-)
emalove emalove 9 years
I thought it was a fact that this happens.
GlowingMoon GlowingMoon 9 years
Yes, it's creepy. This happened among my close girlfriends, too, and we didn't live together. We were just close friends. Weird!
aimeeb aimeeb 9 years
This totally happens!
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