Can progesterone prevent spontaneous abortion? Let me explain it to you one by one

As we all know, progesterone (abbreviated as "progesterone") is a female hormone belonging to the progestogen (also known as "luteinizing hormone") class. Luteinizing hormone can cause secretion-like changes in the endometrium affected by estrogen, which is one of the essential prerequisites for the successful implantation of the fertilized egg.

Medically, a considerable number of women who have spontaneous abortions during early pregnancy are due to insufficient secretion of progesterone. Therefore, for many years, both developed and developing countries, including my country, have widely used progesterone as a drug for preventing and treating abortions in early to mid-term pregnancy.

So, is progesterone really effective in preventing and treating miscarriage? How about its safety? Professor Haas, Professor Wahab and others searched all relevant databases around the world for randomized and semi-randomized controlled trials comparing progesterone with placebo (or no treatment) in preventing and treating miscarriage. In order to obtain the necessary information, the scientists also communicated with some authors of published papers and contacted experts in the field to find any unpublished articles. Based on these data, they made an evidence-based medical evaluation.

The analysis results show:

① There was no statistically significant difference in reducing the risk of miscarriage between the group receiving progesterone and the placebo or no treatment group [Peto odds ratio (Peto OR) was 0.98; 95% confidence interval (CI): 0.78–1.24].

② Similarly, different routes of progesterone administration, oral, intramuscular or vaginal, did not show statistically significant differences in reducing the incidence of miscarriage.

③ Interestingly, four small trials (three of which were published 40 years ago and one in 2005) reported that in a group of women with recurrent miscarriages, the use of progestins reduced the miscarriage rate compared with the placebo group, and it was statistically significant (OR, 0.37; 95% CI: 0.17–0.91).

④ The use of progesterone has no adverse effects on women. Although women who receive progesterone treatment have been found to have a slightly increased risk of adverse outcomes for the fetus and newborn (such as fetal malformation and neonatal death), the number of cases is too small (partly because such adverse outcomes are uncommon) to be considered a potential risk.

⑤ Another separate analysis involving only two studies of low methodological quality and 84 cases of threatened abortion (the most common clinical diagnosis requiring progestin treatment) showed that there was no evidence that vaginal progesterone could effectively reduce the risk of miscarriage in women with threatened abortion (relative risk RR, 0.47; 95% CI: 0.17−1.30).

Finally, these medical experts believe that progesterone has no preventive and therapeutic effect on miscarriage in early to mid-pregnancy. At the same time, medical scientists believe that all the trials included in the review were conducted in developed countries, but the results are also applicable to developing countries.

The most important outcome of these reviews is to raise awareness among policy makers, health care providers, and women at risk of miscarriage that there is no evidence-based basis for the use of progestins in the treatment of threatened miscarriage.