Factors associated with successful induction of labor.

OBJECTIVES: To evaluate the prevalence, indications, and factors associated with successful induction of labor (IOL), and maternal and neonatal outcomes.

METHODS: All women booked for IOL at King Khalid University Hospital, King Saud University, Riyadh, Kingdom of Saudi Arabia from April 2010 to March 2011 were included. The characteristics of women who had successful IOL were compared to those who delivered by cesarean section (CS). A multivariable logistic regression analysis was performed to evaluate the factors associated with successful IOL.

RESULTS: During the study period, 564 women had IOL. The prevalence rate of IOL was 16%. Vaginal delivery was achieved in 472 (84%) women. The most common indications for IOL were post-term pregnancy in 174 (31%), and diabetes mellitus in 131 (23.2%) of the participants. Maternal characteristics associated with risk of CS were nulliparity (odds ratio: 1.58; 95% confidence interval: 1.09-2.320; p=0.01), and high maternal body mass index (p=0.01). Neonates of women with successful IOL had significantly higher APGAR scores (p=0.04), and more frequent pH more than or equal to 7.1 at delivery (p=0.02). There was no difference in the rate of post-partum hemorrhage, CS, or ruptured uterus between the women who had IOL, and those who went into spontaneous labor.

CONCLUSIONS: Nulliparity and maternal weight are the main determinants of the outcome of IOL. Case selection for IOL is vital for achieving outcomes similar to spontaneous labor.