[Intervals for increasing the dosage of oxytocin]

We retrospectively analyzed 468 deliveries in 1989, 935 deliveries in 1990, and 1020 deliveries in 1991 from cephalic presentation. Oxytocin was given for reason of not sufficient labor (cervical dilatation < 1 cm/hr) after spontaneous or artificial rupture of membranes. Oxytocin was increased at intervals of 20 minutes (in 1989) or 60 minutes (in 1990 and 1991). The percentage of deliveries augmented with oxytocin, the cesarean section rate in deliveries with or without oxytocin, the maximum oxytocin dose, and the condition of the neonates (arterial cord blood pH value, Apgar scores at 1 and 5 minutes) were compared. Prolonging the interval of increasing oxytocin did not adversely influence the condition of the neonates and was not associated with a significant change in the cesarean section rate. The average duration of oxytocin administration was prolonged slightly, but the maximum dose and therefore the average total dose administered were decreased.