I was prescribed Naproxen to reduce menstrual bleeding, but...

[Headsquirrels]

Brief history - I started getting nightmarishly heavy periods about a year ago and finally gave in and saw a doctor last month. She's booked me in for blood tests and scans but also prescribed me Naproxen and said it can lessen menstrual bleeding by up to 30%. Okay, so I do some Googling and even though the 'net says yes, it can be prescribed for that, I can't find any sources that explain HOW it works.

My GP told me to take one tablet twice a day for every day of bleeding (preferably starting the night before if my cycle is regular – which thankfully, it is). I'm on my second period since I got the prescription and it does indeed seem to be having an effect. In fact, my period started and then just kind of stopped dead again this time around!

And here's where I'm full of confusion... periods happen after the uterine wall thickens in preparation for possible fertilised egg, and then the blood loss happens when no such egg occurs. But then HOW can a pill taken the day before or on the day of your period somehow magically reduce the loss of the lining? Surely it's already there, and has to go SOMEWHERE? Does it get reabsorbed into your body or something?

More Googling yielded no answers, and a friend of mine who works in healthcare said that's pretty standard for a lot of drugs that end up getting used off-label to treat other things (Naproxen is primarily prescribed as an anti-inflammatory), and especially such discoveries in women's reproductive health, because the effort of further research doesn't seem to be a priority and we just get the "well it works but we don't really know why". Because patriarchy.

I would be VERY interested to hear from anyone who actually knows why Naproxen can lessen menstrual bleeding. I mean sure, I'm happy that it's helping me, but it's driving me bonkers that I can't figure out how.

[Musicaltheatremum]

It is to do with its effect on prostaglandin synthesis. I think by reducing prostaglandin the spiral arteries in the uterus tighten up so there is less bleeding. I remember talking about this very point with the external examiner in my medical finals in 1986!! I'd have to look up the exact science behind it but it's roughly that.

[Headsquirrels]

Thanks for that! My mind still can't get around where the blood goes though. Unless it reduces the bleeding by making your period longer - basically so it's coming at a slower pace?

[Walkingthroughawall]

Yup, agree it's to do with constricting the blood vessels and IIRC they improve platelet function.

What comes out during period is a combination of dead cells, mucus and blood. If you constrict the blood vessels to the lining of the uterus, then less blood can get out of them and it just stays in your vascular system. There isn't a pool of blood sitting in your uterus just waiting to fall out, it's all in blood vessels as part of the normal circulation and if you take naproxen that just means that that blood stays in the circulation rather than coming out. By improving platelet function you're also more likely to get a clot form at the bleeding point of the blood vessels so less blood can get out of the vessels. You'll still shed the dead endometrial cells, mucus and whatnot, but there'll just be less fresh blood coming out with it.

Hope that helps. Physiology is brilliant!

[Headsquirrels]

Walkingthroughawall - thank you SO much, that's supremely helpful! :)

[Musicaltheatremum]

Thanks walking for reminding me of the finer details. Glad I was still on the right track. 😂