The authors conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate progesterone, as compared with placebo, in women with vaginal bleeding in early pregnancy. The findings suggest that among women with bleeding in early pregnancy, progesterone therapy administered during the first trimester did not result in a significantly higher incidence of live births than placebo.
Siew JY, Allen JC, Hui CY, Ku CW, Malhotra R, Østbye T, Tan TC. The randomised controlled trial of micronised progesterone and dydrogesterone (TRoMaD) for threatened miscarriage. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2018 Sep 1;228:319-24.
Ku CW, Allen Jr JC, Lek SM, Chia ML, Tan NS, Tan TC. Serum progesterone distribution in normal pregnancies compared to pregnancies complicated by threatened miscarriage from 5 to 13 weeks gestation: a prospective cohort study. BMC pregnancy and childbirth. 2018 Dec;18(1):360.
Wang XX, Luo Q, Bai WP. Efficacy of progesterone on threatened miscarriage: Difference in drug types. Journal of Obstetrics and Gynaecology Research. 2019 Jan 10.