5 little-known facts about your period

12. Women experience more brutal periods during the colder months.

A period’s pain level, blood flow, and duration tend to be longer during the winter months than in summer.

13. Science still doesn’t know whether it’s true that women who live together wind up synchronizing their periods.

Although many women swear that they always wind up having their periods around the same time as their close friends, science has yet to definitively answer whether this legend is true.