Women with histories of miscarriage do not experience any significant increase in successful births by undergoing progesterone therapy during the first trimester of pregnancy, according to a new study published Nov. 25 in the New England Journal of Medicine.
“Our results do not support earlier findings of a Cochrane analysis that suggested a benefit of progesterone therapy in the first trimester of pregnancy,” wrote Dr. Arri Coomarasamy, professor of gynecology at the University of Birmingham in Edgbaston, England, and his associates, referencing the 2013 review of 2,158 women across 14 randomized trials, which found that progesterone therapy administered in the first trimester can increase the likelihood of having a successful birth without risk of adverse effects on either the mother or infant.
For the current study, known as the PROMISE trial, the investigators randomized 836 women into cohorts of 404 (progesterone therapy) and 432 (placebo). The progesterone therapy regimen consisted of vaginal suppositories of 400 mg micronized progesterone, inserted twice daily, through 12 weeks of gestation. Those in the placebo cohort also were given vaginal suppositories twice a day for the same duration of the pregnancy (N Engl J Med. 2015;373:2141-8).
Of these women, 826 (98.8%) had follow-up interviews – 398 in the progesterone cohort and 428 in the placebo cohort. Primary outcome (live birth after at least 24 weeks of gestation) occurred in 262 (65.8%) of the women in the progesterone cohort and 271 (63.3%) of the women in the placebo cohort (P = .045). Investigators concluded that there was no significant statistical difference in outcomes between progesterone therapy and placebo based on these results.
The PROMISE study was funded by the United Kingdom National Institute of Health Research. Dr. Coomarasamy did not report any relevant financial disclosures.