Background: Prolonged labor is associated with known complications. There are different reports about initial dose and dosage interval in induction of labor. This study was conducted to compare the effectiveness and complications of two different oxytocin regimens for induction of labor. The differences between them include: starting dose (mu/min) incremental increase (mu/min) and dosage interval.

Materials and Methods: A randomized clinical trial study was performed in Akbar Abadi Teaching Hospital between oct-march 2001 on 110 pregnant women with 41, completed weeks of pregnancy with bishop score ≤4 in protocol A (50 women) (Low-dose oxytocin), oxytocin was initiated at 2/5 mu/min, with 2/5 mu/min incremental increases every 15 minutes until maximum dose 40 mu/min. In protocol B (60 women) (high-dose oxytocin), oxytocin was initiated at 5 mu/min with incremental increases every 45 minutes until maximum dose 40 mu/ min. Then the effectiveness and complications of two protocols were compared.

Results: the duration of induction- to- active phase of labor, was significantly shorter in high dose protocol B. (P<0.001). The duration of induction-to-delivery was significantly shorter in high dose regimen (Protocol B).(P<0.001). The duration of active phase of labor was significantly shorter in protocol B (High dose regimen) (P<0.01). Complications including, hyperstimulation, fetal distress and cesarean deliveries were the same in two groups.

Conclusion: High dose oxytocin regimen is more effective than low dose oxytocin with no more complications and is suggested for induction of labor.