Comparing effects of oxytocin bolus and infusion in the third stage of labor on maternal hemodynamics and the outcome of delivery

Post partum hemorrhage (PPH), with a prevalence of 5%, is one of the most important obstetric emergencies. Oxytocin infusion in the third stage of labor is used to control PPH. Some studies indicated that the oxytocin bolus is more effective than its infusion. This study was performed to compare the oxytocin bolus and infusion effects on maternal hemodynamics and also the outcome of the third stage of labor. This double-blinded clinical trial was carried out on 200 normal vaginal delivery (NVD) patients of Shabihkhani Hospital in Kashan during 2006-2007. Gestational age≥20 weeks, parity≤5, and Iranian nationality were considered as including factors. Excluding factors were over-distended uterus, previous PPH history, hypertension, previous diseases, placenta previa, abruption, history of instrumental delivery or precipitated labor. Patients were divided into 2 equal groups (n=100): the case group received 10 IU oxytocin bolus post- delivery and the control group received 10 IU oxytocin infusion with a rate of 125 cc/h. Maternal hemodynamics and the outcome of the third stage of labor were compared in both groups. Data were analyzed using t-test, Fisher and Chi-square tests. Both groups were matched in terms of maternal age, gestational age, parity, birth weight and duration of the second stage of delivery. Hemodynamic findings showed no significant difference between the two groups in terms of pulse rate of pre- and 1, 10, 20 min post-delivery, but it was significant for 5 min post-delivery (p=0.02). Systolic and diastolic blood pressures had no significant difference between the two groups and in 1, 5, 10 and 20 min post-delivery, however the different outcome findings indicated a shorter duration of the third stage of delivery in bolus group than in the infusion one (p<0.0001). However, no significant difference was seen in terms of requirement for uterotonic agents, hemoglobin and placental retention. While the oxytocin bolus could not change the maternal hemodynamic status, it reduced the duration of the third stage of labor.