Guest Author - Krissi Danielsson

Progesterone, if you haven't heard of it already, is a hormone of pregnancy. It's probably one of the most controversial subjects you'll find out there with regard to miscarriages. Okay, maybe less controversial than immunotherapy, but still you get the idea.

Progesterone is what causes the uterine lining to develop properly and is supposed to be secreted by the ovaries until the placenta takes over progesterone production around week 10 to 12 of a pregnancy. Scientists have known for a long time that progesterone levels tend to decrease when a woman is going to miscarry, so the theory is that low progesterone levels may somehow cause miscarriages and that supplementation could theoretically prevent the miscarriage.

If you're reading this article, you're probably curious about whether or not you should be on progesterone after a miscarriage. You may be confused about the issue because your doctor either presented it as a given that you'd go on progesterone with your next pregnancy -- or he/she may not have mentioned it at all.

To give you the short answer, no one really knows for sure. As mentioned above, progesterone supplementation is controversial. Trials that show benefit to progesterone supplementation are few and far between. A Cochrane Review on the matter reviewed 14 trials and found no statistical evidence that using progesterone supplements reduced the miscarriage rates for women who had one miscarriage prior to the trial. Cochrane Reviews are generally felt by the medical community to be a fairly definitive word since they usually compile results from multiple prescreened trials in order to generate results of statistical significance.

But the same Cochrane Review also found evidence that progesterone supplements might help women with recurrent miscarriages, stating, "In a subgroup analysis of three trials involving women who had recurrent miscarriages (three or more consecutive miscarriages), progestogen treatment showed a statistically significant decrease in miscarriage rate compared to placebo or no treatment (OR 0.39, 95% CI 0.17 to 0.91)." Then it went on to call for more trials in patients with recurrent miscarriages.

So what does this mean for you? Well, progesterone supplementation -- at least with plant-derived natural progesterone (such as prometrium or compounded suppositories) -- is not thought to be risky in any way, so many doctor prescribe it with the idea that it might help and isn't likely to hurt. Many doctors who do prescribe it have anecdotal evidence of progesterone supplements helping women to carry to term after several miscarriages. Other doctors don't prescribe it at all because they feel that the evidence isn't all in yet and they don't want to prescribe potentially useless medications, just in case they might indeed be harmful but the harmful effects haven't been discovered yet (and if you've heard of DES, another medication that was once prescribed to women to prevent miscarriages, then this position is not without merit).

Whether or not to seek progesterone supplementation after miscarriages thus becomes between you and your doctor, like so many other things.

If you do pursue progesterone supplementation, it's probably best to get it through a prescription for some type of natural progesterone -- which again, is either oral prometrium or vaginal suppositories compounded by your local pharmacy. The benefit of using prescription progesterone as compared to store-bought over the counter creams is that you can use a controlled dose that can be monitored by your doctor. With a cream, it's hard to know how much of the medication your body would be absorbing.