The effects of intramuscular administration of corticosteroids on the induction of parturition.

Our purpose was to examine the hypothesis that corticosteroids, when administered intramuscularly, can enhance the labor process and reduce the time interval between the induction and the active phase. A randomized, controlled study was conducted on 66 women with gestational age of 41 weeks and over and favorable cervix (bishop score > or = 7). The study group (n = 32) received 10 mg of dexamethasone phosphate intramuscularly in two doses at an interval of 12 hours, and the day after the enrolling administration intravenous oxytocin was given. The control group (n = 33) received only intravenous oxytocin 24 hours after enrolling. The number of patients to enter the active phase of labor was significantly higher in the study group than in the control group (n = 33 [100%] vs n = 29 [87.9%], p < 0.039). The mean time interval between induction of labor and the active phase was significantly shorter in the study group than in the control group (1.7 +/- 1.5 hours vs 4 +/- 1.7, P < 0.0001), and the mean of oxytocin dose was significantly lower in the study group (1.15 +/- 1.5 u vs 4.16 +/- 2.5 u, P < 0.0001). Induction of labor with the use of intramuscularly injected dexamethasone phosphate reduced the time interval between the induction of labor and the active phase.