Clinical Pearls & Morning Reports
Published May 8, 2019
Miscarriage affects one in five pregnancies. Coomarasamy et al. conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate whether treatment with progesterone during the first 12 weeks of pregnancy would result in a higher incidence of live births after at least 34 weeks of gestation among women with vaginal bleeding in early pregnancy than placebo. Read the Original Article here.
Q: What are the sources of progesterone in early pregnancy?
A: Progesterone, which is produced by the corpus luteum in the ovary, is necessary to prepare the endometrium for implantation of the embryo and thus is an essential hormone for a successful pregnancy. Additional progesterone is produced when an embryo implants in the endometrium and during early placental development. Subsequently, beginning at approximately 12 weeks of pregnancy, the placenta becomes the dominant source of progesterone.
Q: Does progesterone treatment during the first trimester increase the incidence of live births after at least 34 weeks of gestation among women with bleeding in early pregnancy?
A: In the trial by Coomarasamy et al., progesterone therapy administered during the first trimester did not result in a significantly higher incidence of live births after at least 34 weeks of gestation than placebo. The incidence of live births after at least 34 weeks of gestation was 75% (1513 of 2025 women) in the progesterone group and 72% (1459 of 2013 women) in the placebo group (relative rate, 1.03; 95% confidence interval, 1.00 to 1.07; P=0.08).
A: In the trial by Coomarasamy et al., there was no significant between-group difference in the percentage of participants who had either a maternal or neonatal serious adverse event (5% [105 of 2025 participants] in the progesterone group and 5% [98 of 2013 participants] in the placebo group), including specifically the percentage of babies who had neonatal congenital abnormalities (3.4% in each group), nor was there any significant between-group difference in the number of maternal or neonatal serious adverse events.
A: The Coomarasamy trial studied a vaginal preparation of progesterone, at a dose of 400 mg twice daily, and it is possible that the results observed with this regimen are not generalizable to women receiving other doses and preparations by other routes. Micronized vaginal progesterone has an identical molecular structure to natural progesterone, whereas other formulations of progestational agents have a different molecular structure and therefore potentially different mechanisms of action and pharmacologic features.