Vaginal micronized progesterone lowers risk of hypertensive disorders of pregnancy

Initiation of vaginal micronized progesterone during the first trimester appears to reduce the risk of hypertensive disorders of pregnancy (HDP) and pre-eclampsia, according to a study.

Researchers conducted a systematic review and meta-analysis of placebo-controlled randomized trials (RCTs) in which the efficacy of vaginal progesterone for the prevention or treatment of any pregnancy complications was evaluated. Multiple online databases were searched for relevant studies.

Absolute event numbers for HDP and pre-eclampsia in women receiving vaginal progesterone or placebo were collected, and these data were meta-analysed using a random effects model. The certainty of the evidence was assessed using GRADE methodology.

A total of 11 RCTs met the eligibility criteria and were included in the meta-analysis. Vaginal progesterone was initiated in the first trimester in three RCTs and in the second or third trimester in eight RCTs.

Pooled data showed that when started in the first trimester of pregnancy, vaginal progesterone reduced the risk of any HDP (two RCTs, n=4,431 women; risk ratio [RR], 0.71, 95 percent confidence interval [CI], 0.53–0.93; I²=0%; moderate-certainty evidence) and pre-eclampsia (three RCTs, n=5,267 women; RR, 0.61, 95 percent CI, 0.41–0.92; I² = 0%; moderate-certainty evidence) compared with placebo.

On the other hand, vaginal progesterone started in the second or third trimester had no beneficial effect on the risk of HDP (three RCTs, n=1,602 women; RR, 1.19, 95 percent CI, 0.67–2.12; I²=9%; low-certainty evidence) or pre-eclampsia (five RCTs, n=4,274 women; RR, 0.97, 95 percent CI, 0.71–1.31; I²=0%; low-certainty evidence).