It is known that progesterone is an essential hormone for maintaining a pregnancy. Naturally, progesterone is secreted by the corpus luteum in the second half of the menstrual cycle. It is also secreted from the corpus luteum during early pregnancy. It prepares the endometrium for implantation. This study evaluated the effect of progesterone supplementation during the first trimester in women with a history of recurrent miscarriages.
Participants in the trial were recruited at 36 different hospitals across the U.K and the Netherlands. Eligible women were ages 18-39 years of age actively trying to conceive after receiving a diagnosis of unexplained recurrent miscarriage. This is defined as three or more pregnancy losses during the first trimester. A total of 1568 participants received 400 mg of progesterone twice daily or a matching placebo after testing positive for pregnancy. The primary outcome measure was birth. Overall, the trial demonstrated that vaginal progesterone supplementation did not significantly increase the rate of live births for women with a history of recurrent miscarriages. I am curious whether the outcomes would have changed if the progesterone was administered orally. Further studies should be conducted to evaluate various routes of administration.