Why do women's periods match up when they live together?

why is it when woman move in together thair peroids end up comming around the same day?

I don't know why, but I have heard of that happening, I think it's kinda funny! Like some sort of female bond or something! Oh well, at least they can all be moody and whatever at the same time and get it out of the way, right?!

I was just talking about this with my best friend litterally 10 minutes ago- We are always the same. They say its common with women who see eachother or hang out a lot. I have no idea why it happens. But it does.

Women's bodies automatically adjust to eachother's pheromones. Whoever has the strongest keeps their period schedule! I believe it's seen as a primal precaution because blood attracts predators and a woman is pretty pungent when she's on her period. So if all the women have it at the same time, it's less of a threat.

Women's bodies would adjust with the moon if we didn't have so much artificial light in our modern day. Women were frequently called out as witches when their periods would align to the moon's phases.

it like gives off some hormones and sh it and I don't know

hmm I was just thinking about it yesterday... it does kinda match uhppp. maybe cus of what you do? lol idunno