Background. Multiparous patients have a higher risk of hyperstimulation and uterine rupture than nulliparous patients. The minimum possible dose of uterotonic drug should be used in induction of labor for multiparous patients to avoid excessive uterine activity, which could increase both maternal and fetal risks.
Methods. One hundred and four women were randomized to either a single dose of 50 µg of intravaginal misoprostol in 24 h, or two consecutive doses of intravaginal 50 µg misoprostol 6 h apart.
Results. The mean induction to delivery interval (789 min [95% CI: 637–941] vs. 576 min [95% CI: 484–667], p = 0.018) and delivery rate within 12 h (63% vs. 83%, p = 0.035) were higher in the two-dose group. The oxytocin augmentation rate (14% vs. 2%, p = 0.03) was higher in the single-dose group. There was a higher rate of clinician input related to suspicious cardiotocographic readings in the single-dose arm ( p = 0.04). There was no statistical difference ( p > 0.05) between the one- and two-dose regimens with respect to the rates of tachysystole (21% vs. 15%), hyperstimulation (3.9% vs. 0%), and meconium staining at delivery (9.8% vs. 13.2%).
Conclusions. The two-dose regimen was most efficient, but both regimens were well tolerated by the fetuses.