Why do periods synch, how?

[Anonymous]

I remember being in college and all 4 of my roommates and my periods literally started amd ended at the same time for several months... how does this happen, why? Its happened with different women as well

[lilBigPotato]

They don't. It's just luck. The same way it would be luck if you had birthday on the same day. With a standard 28 day cycle, you have a 1/28 chance of it being on the same day. With 4 girls, it's 1/28*1/28*1/28 chance.

[ElenaLena]

Periods don’t actually sync scientifically.. it’smostly coincidence because cycles naturallyvary each month.. it happens to me at work too, whenever someone mentions their period, I feel like mine is coming too…😄

[Brain_Borrower]

What kind of depth of an answer are you looking for on here? something google won't tell you?

[jahaims]

They don't. Google it

[LotharioENERZY]

some guy should interupt it. LOL

[Anonymous]

Ask a doctor.