Background: Labour induction is one of the most common medical procedures in obstetrics. The aim is to end the pregnancy when continuity is a risk to mother or fetus. Its main side effect is the increase in the cesarean rate, compared to spontaneous onset deliveries. On the other hand, mortality and morbidity in cesareans are higher. The most common pharmacological drugs used for induction are prostaglandins: dinoprostone and misoprostol. The “gold standard” for labour induction is vaginal misoprostol. The oral route is also effective and also has several benefits like faster onset and easear administration. In recent years several publications state that the administration of misoprostol oral solution, given in doses gradually, is associated with a lower cesarean and hyperstimulation rate than the cases where vaginal misoprostol has been used in pregnant women with unripe cervix. Furthermore, being its half life shorter, it may be very useful in case of uterine hyperstimulation and, probably, a high percentage of women prefer this oral administration to the vaginal one. The objective of this study is to compare the efficacy, safety and side effects on mother and fetus on use of oral versus vaginal administration for induction of labour for prolonged gestation (41 weeks) and premature rupture of membranes, both with live fetus. Methods/Design: Design: double blind controlled trial. Study population: Pregnant women whose labour will be induced due to premature rupture of membranes or prolonged gestation. Inclusion Criteria: 1) Bishop Test equal to or less than 7; 2) Single pregnancy; 3) Pregnancy at term (37 - 42 weeks); 4) No history of uterine surgery; 5) Cephalic presentation; 6) Live fetus; 7) No prostaglandins contraindications. Discussion: Nowadays induction rates are very high, ranging from 25% to 30% approximately. In these cases caesarean rates are higher than when the delivery starts spontaneously. That is one of the main reasons why caesareans have increased, mainly in the cases of nuliparous women with immature cervix. If we can prove the hypothetical good results obtained through the use of dosed oral misoprotol, we will be able to reduce the number of induced deliveries by cesarean, and so improve the levels of security for the mother and the foetus, and, as a consequence, provide a higher quality of medical attention to the newborn and the mother.