Threatened miscarriage is a common complication of pregnancy occurring in 20% of all clinically recognized pregnancies, and about half will eventually result in complete pregnancy loss. But current treatment of threatened miscarriage showed no benefit when compared with placebo. Our aim is to investigate the effectiveness and safety of Chinese herbal medicine (CHM) and/or oral micronized progesterone (OP) in women presenting with threatened miscarriage. The new “Shoutai Wan” (NSTW) granule CHM is used.

This is a multicenter, randomized, placebo-controlled factorial trial with a 2 by 2 design. It is currently being conducted at 22 sites in mainland China. We plan to enroll women with threatened miscarriage at 5–10 gestational weeks. After screening, randomized assignment will be conducted for eligible women by a computer generated random block format in a 1:1:1:1 ratio into one of four groups: 1) CHM and OP; 2) CHM placebo and OP; 3) CHM and OP placebo, and 4) CHM placebo and OP placebo. Depending on the gestational age at randomization, the medication will be administered for 2–7 weeks, ending at 12 weeks gestation. The primary outcome measure is live birth. Secondary outcomes are: 1) pregnancy outcomes, including rate of sustained ongoing pregnancy rate, miscarriage, stillbirth, induced abortion, preterm birth, extreme preterm birth, full-term birth, post-term birth, and delivery gestational age; 2) neonatal outcomes, including rate of small for gestational age, large for gestational age, congenital malformations and birth weight; and 3) maternal outcomes, including score change of SF-12 Health Survey Scale, Zung Self-Rating Anxiety Scale, and Traditional Chinese Medicine Symptom Score. The sample size is 1656 participants.

This trial is expected to provide strong evidence regarding the efficacy of CHM and OP for threatened miscarriage management.

The trial is registered at clinicaltrials.gov (approval no.: NCT02633878). Last refreshed on October 31, 2024.