This Period Thing We Never Knew Existed is Gross AF

​Periods may get a lot of stick from those who don't know much about them (men) but really, they're not that bad. We've been well-versed since our early teens to recognise the arrival of our monthly bleed a mile off, and to just deal with it for the following five or so days.

At worst, it's a bit inconvenient.

Well, that's what we thought until we stumbled across THIS on the world wide web: a decidual cast. And now we're feeling a bit aggy about periods altogether. Don't know what it is? No, us neither until this week, and we've been wondering how to permanently forget about it ever since.

A decidual cast is an actual thing where a woman's uterus, instead of shedding its lining across the best part of a week, decides to evacuate all in one go. And just to make it extra gross, instead of being like some kind of tidalwave-esque gush, it emerges from you ​in the shape of your insides​. 

Internet Scientific Publications have published a report on the medical instance, which is most common in pregnant women (more specifically with ectopic pregnancies) but is not unheard of for those who aren't or haven't recently been carrying a child.

In the paper, it describes ​a decidual cast as this:

The lining of the pregnant uterus, other than the area taken up by the placenta, is called the decidua. The appearance of the normal lining of the uterus, by the effect of progesterone, can become decidualized .When an area of decidua is shed, it is called a decidual cast because it frequently comes out in the shape of the uterine cavity. ​

And it t looks like some kind of rams head, for real. But we reckon that must be the fallopian tubes or something​.

***HI, IF YOU DON'T WANT TO BE FOREVER DISTURBED WE SUGGEST YOU SHUT YOUR EYES AND SCROLL***

***SCROLL SOME MORE***

***AND MAYBE A BIT MORE***

Sorry, but we did warn you. This is what it looks like from underneath...

Yeah, so there you go. And although it's probably not something you've ever come across before, it is surprisingly common. Two Reddit users, in fact, have described discovering their own decidual casts, and having had to Google it to know what the eff it was.

Indiana_meg:

"So I'm having my period, and it's WAY crampier than usual. I curled up around a hot water bottle for the entire 4th season of Community last night and then slept with this water bottle too. It wasn't the usual achey cramps but the super stabby cramps that radiate down the lower back.

"Fast forward to today. I'm changing my tampon and the nastiest blood clot I've ever seen in my life is dangling out of me. I give it a tug with some toilet paper and this huge mass of white tissue comes out with it. I drop some f-bombs and I'm terrified it's a weird mass of fetal tissue and I just had a miscarriage after not knowing I was pregnant and this queues up a whole lot of anxiety.

"Doctor Google, however, tells me it's a Decidual Cast, or "My Uterus Just Tried To Shed Its Entire Lining In One Go". Google this for some descriptive and nasty photos (Or just imagine a uterus shedding its skin like a snake and you're left with a replica of your uterus that escapes out through your vagina."

Ipromiseitsnotglue:

"I recently got the implanon (1 month) and I've just started spotting. I was standing up and got that clumpy oozey feeling you get when your about to pass a huge chunk of tissue. So afterwards I got to inspect the damage and if I have to change liners and I have something like this. I didn't take a picture of my own cause I was a little weirded out but I was google searching. Apparently it's some sort of shedding of uterine lining and happens with progesterone.​"

Well, you learn something new every day.