Oral, double-blind administration in 2 groups of 20 patients each of a placebo versus 100mg Mifepriston given morning and evening for 48 hours, shows that this progesterone antagonist exerts a softening and dilating effect on the uterine cervix. This effect facilitates the instrumental dilation required for termination of pregnancy on the first trimester. While effective and free of side effects, this technic for cervical preparation has the further advantage of being nearly painless and thus may be applied to out-patients.