Oral dydrogesterone for prevention of miscarriage in threatened miscarriage: a randomized, double-blind, placebo-controlled trial.

Objective: To determine the effectiveness of oral dydrogesterone in preventing miscarriage in threatened miscarriage.

Methods: A randomized, controlled trial study was conducted among pregnant Thai women at the gestational age of six to less than 20 weeks who visited King Chulalongkorn Memorial Hospital, Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand with threatened miscarriage from August 2021 to August 2022. These pregnant women were randomized to receive oral dydrogesterone 20 mg per day or placebo twice a day until one week after vaginal bleeding stopped or otherwise for a maximum of six weeks.

Results: A total of 100 pregnancies were recruited. Fifty of them were assigned to receive oral dydrogesterone and 50 were assigned to receive placebo. The rate of continuing pregnancy beyond 20 weeks of gestational age was 90.0% (45 out of 50 women) in the dydrogesterone group and 86.0% (43 out of 50 women) in the placebo group (p = 0.538). The incidence of adverse events did not differ significantly between the groups.

Conclusion: Oral dydrogesterone 20 mg/day could not prevent miscarriages in women with threatened miscarriage.