This article was originally published on February 11, 2016.
The menstrual cycle is one of the more confusing and sometimes frustrating (but honestly, also kinda cool) things about having a female body. In the fascinating video above from Nova, host Anna Rothschild takes us through three major questions many of us have probably had about our periods at one time or another. And yes, consider this a TMI-free zone, as any conversation about menstruation should be.
The second question Rothschild tackles is easily the number-one query that comes to mind for many women: Why do I have to poop so much when I have my period? This problem can make it feel like your entire lower half is revolting against you (this on top of cramps?!), and for that you can blame two bodily chemicals: prostaglandins and progesterone.
For their part, prostaglandins signal the uterus to contract so your body can push out the uterine lining. And sometimes, these hormone-like chemicals can also affect your digestive organs nearby, making you gassier and have to go more often than you do on your non-bleeding days.
Progesterone is a natural hormone that your ovaries produce. Throughout your cycle, your levels of progesterone gradually rise, peaking right before your period and then dropping dramatically. Though it's known as "the pregnancy hormone," progesterone has an interesting side effect: It's slightly constipating. So when those levels drop for your period, it can "loosen" you up, as Rothschild puts it.
She also addresses pressing matters like what your period blood really contains (immune cells, vaginal secretions, cells from the endometrial lining, and, of course, actual blood) and which animals, besides humans, have regular periods.
Check out the full video above for more fun facts about periods — so intriguing, you'll want to share them at your next dinner party.