Hey Anon! I was on medroxyprogesterone (also known as Provera). I was on it since I wanted to TTC and hadn't had a period in 6 years. I was prescribed 10mg for 14 days. Here's my experience...
You are suppose to take Provera after ovulation. Seeing as I didn't have a cycle in so long my gyn went ahead and gave me it anyway. 10 days on the pill and I ovulated. The pill is not good to be taken during pregnancy but after discussing with my gyn we went ahead with it as any possible chances were very, very slim.
I took it for the remaining 4 days, totalling 14 days of taking it. On day 14 my breasts were aching, I had terrible cramps. My period arrived 3 days later. [Note: After taking your last pill of Provera, your period will start between 1-14 days later.] Mine started at 3 days because I hadn't had it in so long. The longer you've been without it the quicker it will show up.
Provera periods are a living hell. I don't want to scare you, just getting you prepared. I called my gyn and a nurse and their advice was "Don't leave the house!" I use to have heavy periods but NOTHING like this. I had a bit of spotting the night prior and then it was instantly heavy. I would go through a super absorbent tampon and pad about every 45 minutes. Just to give you an idea. So if you can stay home, I advise it. The cramps left about a day after the period started. The period lasted 8 days but can last up to 14 days, most common is between 8-10 days I read.
After taking Provera I ovulated on cd14 (This isn't always the case. Provera doesn't cause ovulation, if anything it prevents it). I can't tell you if I got pregnant that cycle or not as I'm currently on cd33 of it! I use to be 28 day cycles when I did have a period. With that said, provera appears to not have regulated me at all. I find out tomorrow if I'm pregnant, and if not I will be going on another 14 days of provera.