This Is What’s Actually In Your Period Blood
Most women under a certain age have a period every month—it’s just part of being a female. And, odds are, you’ve been dealing with your period since you were a teenager. But have you ever wondered what, exactly, your period is made up of?
It’s actually not what you’d think. Sure, there’s blood in the mix but that’s not the only component. “Period blood is made up of thickened endometrial cells that slough off if there isn’t a pregnancy, actual blood from arteries in the uterus, and sometimes clots,” women’s health expert Jennifer Wider, M.D. says.
Let’s back up for a second: During your cycle, a lining is formed in your uterus to make an appropriate, nourishing bed for a fertilized egg, Maureen Whelihan, M.D., an ob-gyn at the Center for Sexual Health & Education tells. This lining, made up of cells and fed by many blood vessels, is called the endometrium, and it first begins to build up with estrogen, which happens for the first two weeks of your cycle. Then, you ovulate and pass an egg, which may or may not be fertilized. The follicle that released your egg makes progesterone (a hormone that prepares your body for pregnancy), which makes the lining stay thick and plush. About 14 days later, if you don’t get pregnant, the hormone levels drop, the lining sheds, and you get your period.
“Your period is just a monthly shedding of the bed that would normally nourish a developing embryo,” Whelihan says.
As for those blood clots, that’s actually just your body trying to do its job. While they can be freaky, Whelihan says they’re really not a reason to panic. “When women come in worried about clot, I tell them it’s a good sign that your body is responding to the increased blood flow by trying to slow down the flow,” she says. These are especially common first thing in the morning, she says, since the blood has time to pool in your vagina while you sleep.
“Our bodies release anticoagulants to stop the menstrual blood from clotting,” explains Wider. “When the period is heavy and coming out rapidly (often in the early days), the anti-coagulants may not have time to work, and clots can form.”
If you’re taking hormonal birth control pills, though, your period blood is slightly different. “When you introduce synthetic hormones into the body, the level of natural hormones gets altered,” Wider says. Basically, “the hormonal changes that would cause a thickening and breakdown of the endometrium doesn’t occur if you’re taking the Pill,” Wider says.
Your body will produce a “flatter” uterine lining when you take hormonal birth control and, in some cases, will create no lining at all, Whelihan says. “That’s why on some of these pills, women don’t bleed much or rarely bleed,” she says. “It’s like a fake period.”