A comparison of induction of labor success rates over three time periods in 20 years at a single academic tertiary care center: are we improving vaginal delivery rates?

OBJECTIVE: To compare the rates of successful induction of labor during three one-year periods over 20 years at a single institution.

METHODS: All women at 37 weeks or beyond with a living, singleton, cephalic fetus admitted for induction of labor in 1992, 2002, and 2012 were included. The use of induction agents and rates of successful vaginal delivery were compared.

RESULTS: A total of 627 women were evaluated, 219 in 1992, 220 in 2002, and 188 in 2012. Various induction agents were employed over the 20 year period. However, the rates of successful vaginal deliveries did not significantly vary over the three time periods, 79.5% in 1992, 72.3% in 2002, 76.1% in 2012, p = .21. In subgroup analysis, no significant differences were found among women with one or more prior vaginal delivery, no prior vaginal delivery, or after excluding those with a prior cesarean section. In multiple variable logistic regression analysis, no induction agent besides amniotomy improved successful vaginal delivery rates.

CONCLUSIONS: Despite the multiple induction agents available at our tertiary care institution over the past 20 years, we were unable to demonstrate any significant improvement in successful vaginal delivery rates after induction of labor.