A randomized controlled trial of two-doses of vaginal progesterone 400 vs. 200 mg for prevention of preterm labor in twin gestations.

Objectives: To compare between the effectiveness and safety of two different daily doses of vaginal progesterone (400 vs. 200 mg) in the prevention of preterm labor in twin pregnancy.

Methods: This is a prospective single-blinded randomized controlled trial conducted on 100 primi-gravida who had twin pregnancy and attended the antenatal clinic of a University hospital.