When we’re PMSing, feeling crampy and moody and awful, it can be really easy to forget the actual reason why we get periods (because it feels like the only REAL reason is because Mother Nature is actually the worst.) However, a Ted Ed video posted yesterday reminds us that periods are actually so incredible — even if they can seem annoying, painful, and downright cruel sometimes.

The video begins by pointing out that we’re one of the very few species to have a menstrual cycle, and we have periods more than any other animal, “even though it’s a waste of nutrients, and can be a physical inconvenience.” Yes. Yes, it can. So why do we get it? To protect our health, that’s why.

Here’s the deal: Pregnant humans are different from other mammals in that the placenta is directly connected to the mother’s circulatory system, which can make a developing fetus super endangering to the mother’s health. It can turn into a “biological tug-of-war” with the fetus being given unrestricted access to nutrient-rich blood, and the fetus can release hormones that can increase the mother’s blood sugar, blood pressure, and dilate her arteries. A little scary. But that’s where your period comes in and saves the day! Er, days.

Periods serve as a sort of “screening system” to make sure our bodies go through this process for only the most promising of embryos. The endometrial wall makes it as difficult as possible for embryos to attach themselves, meaning only the strongest are able to do it. But even if an embryo makes it to the uterus, it can still cause infections or endanger the mother’s health, so the endometrial lining is shed every single month if there’s no healthy pregnancy. That is, the body yells, “NO HEALTHY PREGNANCY? GET RID OF IT ALLLLLL” and your period starts. So it’s all for your health, even if it can be a little bit painful and exhausting sometimes.

During your next cramps, pat your uterus and say, “Hey, thanks for lookin’ out for me,” then eat some chocolate. Because let’s be real: this information doesn’t make cramps any easier, but at least we know it’s just our body having our back. Check out the video below, because it’s pretty great.

(Image via YouTube.)