RESUMEN
OBJECTIVE: To compare the safety and effectiveness of vaginal misoprostol 25 µg with those of 50 µg in induction of labor. METHOD: One hundred and sixty eligible women of low parity with indications for induction of labor at term were enrolled for the study. The subjects were randomized into two groups of vaginal misoprostol 25 µg and 50 µg dose regimens. Maternal characteristics, labor and newborn outcome were compared. RESULTS: The total duration of labor was significantly shorter in the 50 µg group (8.24 ± 1.5 h) than 25 µg group (9.09 ± 2.7 h), p = 0.02. Oxytocin augmentation was significantly higher in the 25 µg group (18.75%) than in the 50 µg group (7.5%), p = 0.04. The indications for caesarean section were significantly different, (p = 0.02) between the two groups although the incidence was similar. The intrapartum adverse effects like fetal distress, meconium stained liquor, and tachysystole were significantly higher in the 50 µg group, p = 0.003. Similarly, the postpartum adverse effects such as cervical and vaginal tears were significantly higher in 50 µg group, p = 0.01. CONCLUSION: The two dose regimens were both effective in induction of labor, but 50 µg dose regimen resulted in significantly shorter duration of labor but with higher rate of labor complications than the 25 µg dose regimen.