Progesterone to prevent miscarriage in women with early pregnancy bleeding: the PRISM RCT

Area of Science:

• Obstetrics and Gynecology
• Reproductive Medicine
• Clinical Trials

Background:

• Progesterone is vital for maintaining pregnancy.
• Early pregnancy bleeding is a common concern associated with miscarriage risk.
• Previous studies suggested progesterone therapy might prevent miscarriage in women with threatened pregnancies.

Purpose of the Study:

• To determine the efficacy of vaginal micronised progesterone in women experiencing early pregnancy bleeding (first 12 weeks).
• To evaluate the cost-effectiveness of progesterone treatment in this patient group.

Main Methods:

• A multicentre, double-blind, placebo-controlled, randomised trial involving 4153 women aged 16-39 with early pregnancy bleeding.
• Participants received either 400mg vaginal progesterone or placebo twice daily until 16 weeks of gestation.
• Primary outcome was live birth at ≥34 weeks; cost-effectiveness analysis was also performed.

Main Results:

• Overall live birth rate was similar between progesterone (75%) and placebo (72%) groups (p=0.08).
• A significant subgroup effect was observed based on previous miscarriage history: women with three or more previous miscarriages had a higher live birth rate with progesterone (72% vs 57%, p=0.004).
• Progesterone was associated with a higher cost per additional live birth (£3305).

Conclusions:

• Vaginal progesterone did not improve overall live birth rates in women with threatened miscarriage.
• Progesterone therapy may benefit specific subgroups, particularly those with multiple previous miscarriages.
• The cost-effectiveness of progesterone therapy is dependent on societal willingness to pay for increased live birth chances.