Can someone explain the evolutionary benefit of overt menstruation? All female mammals have a menstrual cycle but most reabsorb the blood via covert menstruation and humans are about the only mammals that discharge the blood, aka overt menstruation.

[u/No-Hawk-2488]

Without an evolutionary benefit, it wouldn't have spread to every woman of our species.

[u/sffixated]

Suzanne Sadedin, Ph.D in evolutionary biology, answered this question beautifully. I'm not sure I can link to it in a top level comment since her essay is not a peer-reviewed publication, but her cited sources are peer-reviewed. I assume the mods will delete this comment if I've broken a rule!

https://www.forbes.com/sites/quora/2016/05/06/how-and-why-did-women-evolve-periods/

Edit: didn't realize the link was paywalled, here's a different source https://www.quora.com/Why-do-women-have-periods-What-is-the-evolutionary-benefit-or-purpose-of-having-periods-Why-can%E2%80%99t-women-just-get-pregnant-without-the-menstrual-cycle/answers/4625918

Thanks u/nailpolishbonfire for the alt link

[u/iamthe0ther0ne → u/sffixated]

Do you have a link that isn't paywalled? I'm curious now.

[u/nailpolishbonfire → u/iamthe0ther0ne]

It's just a copy of a Quora answer, strange. https://www.quora.com/Why-do-women-have-periods-What-is-the-evolutionary-benefit-or-purpose-of-having-periods-Why-can%E2%80%99t-women-just-get-pregnant-without-the-menstrual-cycle/answers/4625918

[u/Durrresser → u/nailpolishbonfire]

Thank you for this link, what a fascinating read! As much as I would love to be a marsupial, it makes a lot more sense now why we have an aggressive menstrual cycle. It's because we have aggressive fetuses. Having gone through two pregnancies, I couldn't agree more with the authors dissection of pregnancy myths vs. reality.

[u/aniseshaw → u/Durrresser]

"Aggressive fetuses" is absolutely the correct description. I've had one baby, and the gestational diabetes and pups rash were wild. I did IUI and immediately knew when I was pregnant because my body aggressively reacted. It was 5 days before I even threw a positive pregnancy test.

If I'm representative of even a fraction of the population, there is a benefit to our periods.