Hi J.,
I'm really sorry to hear about the miscarriages. I also had one last year, and now am 4 weeks pregnant and crossing my fingers. I don’t know a lot about the progesterone therapy, but I think it’s good that your doctor is recommending it, to me it appears he’s being more cautious. I believe I have luteal phase issues that may have caused a miscarriage (based on the dating from the ultrasound, before fetal demise), and from charting that I was doing. But, luteal phase defects are still theoretical with doctors on either side of whether or not it is an issue in pregnancy, and my doctor is one of the skeptical ones. There is one scientific study that showed that women who’d experienced previous miscarriages had lower miscarriage rates when using progesterone therapy in the first 12 weeks of pregnancy. I haven’t read anything about using it later in pregnancy, but I’d trust your doctor on that unless you have some research that shows otherwise. I wanted to try to use progesterone cream to regulate my cycle (I had several signs of estrogen dominance) and help me get pregnant, and I did it without telling my doctor because I knew she didn’t really think there was an issue (I’d read of other women doing it without telling their dr.). When I found out I was pregnant, I did come clean and tell her that I’d been using it, and was wondering if I could keep using it. She said to go ahead and keep using it, it couldn’t hurt anything. She didn’t want to test my progesterone level because she felt there’s a large range of normal (I still don’t know why not, seeing as there’s still a range, and one could be under it, although it may’ve been skewed by my use of the cream). It’s hard to argue with a doctor over things you’ve read on the internet, that they’ve probably also read and already dismissed as not having enough evidence to be worth considering.
I wouldn’t worry about using it. Progesterone seems a harmless enough hormone to supplement, and your doctor will be monitoring your levels. The progesterone may make you sleepy, but I haven’t noticed anything else. I do know that once you’re on it, you need to stay on it steadily and wean off of it, because withdrawal can cause miscarriage. I feel fine about the cream because it's plant derived (yam), and that's supposed to mimic what we naturally produce. You can try looking the difference between natural and synthetic up on the internet and talk with your doctor about it if you're more comfortable with the natural. If you use cream, be careful of the ingredients. Some essential oils are contraindicated in pregnancy. I get the plain Emerita stuff, and Vitamin Shoppe has the best price online (pretty cheap, actually, and I ask the store to match the online price).
Best wishes for a happy, healthy pregnancy soon and baby!