Objective: To compare the efficacy of two different dosages of oral misoprostol (50 and 100 microg) with control, in medical induction of labor for patients with prelabor rupture of membranes (PROM) at term.
Methods: One hundred women with PROM at term were randomized to receive placebo (vitamin B6 50 mg, control), 50 microg (treatment group 1), or 100 microg (treatment group 2) of oral misoprostol every 4 h to a maximum of six doses. The main outcome measures included time interval from onset of PROM to delivery, duration of first stage of labor, and occurrence of vaginal delivery within 24 h from PROM.
Results: The time intervals from PROM to delivery were significantly reduced in both treatment groups compared to control (control, 25.1+/-10.5 h; treatment group 1, 14.5+/-6.2 h; and treatment group 2, 13.0+/-6.1 h, p<0.0001 for both). The duration of the first stage of labor was significantly shortened only in treatment group 2 compared to control (3.3+/-2.5 versus 6.2+/-3.4 h, p=0.01). Of those who delivered vaginally (93% in treatment group 1 and 97% in treatment group 2), significantly more women delivered within 24 h of PROM in the treatment group compared to the control group (50%, p<0.05).
Conclusions: Oral misoprostol 50 microg every 4 h is safe, cheap, and as effective as 100 microg in reducing the PROM to delivery time interval and labor duration in primiparous women. The same effect is not observed in a multiparous group.