[Low dose of sublingual misoprostol (12.5 µg) for labor induction]

To describe the maternal and perinatal outcomes after the use of 12.5 µg of sublingual misoprostol for labor induction in women with term pregnancy and a live fetus.

We conducted a multicenter, open and non-randomized clinical trial during the period from July to December 2009. We included 30 pregnant women with an indication for labor induction at term, carrying a live fetus, with a Bishop score of six or less, cephalic presentation, estimated fetal weight of less than 4,000 g and an amniotic fluid index greater than five. We excluded women with a previous uterine scar, non-reassuring fetal status, congenital anomalies, multiple pregnancy, intrauterine growth restriction, genital bleeding, and contraindications of vaginal delivery. A tablet of 12.5 µg sublingual misoprostol was administered every six hours, until the beginning of labor, with the maximum of eight doses.

Labor was successfully induced in 90% of pregnant women. The mean interval between the first dose and the onset of uterine contractions and delivery was 14.3±11.7 hours and 25.4±13 hours, respectively. The frequency of vaginal delivery was 60%. Uterine tachysystole occurred in two pregnant women, being reversed in both cases without the need for cesarean section. Meconium-stained amniotic fluid was observed in four patients, and an Apgar score of less than 7 at five minutes in only one newborn.

Maternal and perinatal outcomes were favorable after induction of labor with sublingual misoprostol at a dose of 12.5 µg every six hours. However, controlled trials are needed to compare this regimen with other doses and routes of administration.