[Titrated oral solution of misoprostol for labour induction: a pilot study]

To test effectiveness and safety of the oral administration of a new misoprostol formulation in titrated doses for the induction of delivery of a live fetus at term.

An open pilot multicenter, non-randomized clinical trial was conducted from July to December 2008. A total of 30 patients with indications for induction of labor were included. The patients had a live fetus, Bishop score <6, vertex presentation, fetal weight <4,000g estimated by ultrasonography and amniotic fluid index >5. Exclusion criteria were previous uterine scar, non-reassuring fetal heart rate tracing, multiple pregnancy, fetal growth restriction, genital hemorrhage and presence of genital tumors, ulcerations or malformations. An initial dose of 20 µg/hour of the oral misoprostol solution was used in the first 6 hours, and was increased progressively to 20 µg/hour every 6 hours if labor did not start, up to a maximum dose of 80 µg/h in the first 24 hours, maintained for additional 24 hours if necessary.

Labor was satisfactorily induced in 96.7% of patients. The interval between the first dose and the beginning of uterine contractions was 3.8 ± 1.8 hours. The interval between the initial dose and delivery varied from 6 to 24 hours. The frequency of vaginal delivery was 80% (24 cases). Most of the patients (60%; n=18) initiated labor with a dose of 20 mg/hour. Tachysystole occurred in 13.3% of women and meconium-stained fluid was detected in 20% of cases. There were two cases of Apgar scores < 7 in the first minute and no Apgar score < 7 in the fifth minute.

The oral solution of misoprostol was effective and safe for the induction of labor. However, further randomized controlled trials are needed to compare this new formulation with misoprostol administered by the vaginal route.