Predictors of successful induction of labour in post-term pregnancies at the Kenyatta National Hospital, Nairobi

Abstract

Background: A prolonged pregnancy poses a threat to the fetal survival in-utero and may compromise
perinatal outcomes. Worldwide 5-10% of all pregnancies are prolonged, and post-datism remains the commonest indication for induction of labour.

Objective: To determine predictors of successful induction of labour in post-term pregnancies at Kenyatta National Hospital (KNH).

Methods: A prospective observational study among post-term pregnant women delivering at KNH.

Results: The success rate of induction among study participants was 68%. Prostaglandins in  combination with artificial rupture of membranes and oxytocin infusion were the commonest used  methods for inducing labour. Multiparity was major predictor for successful induction of labour; 55% in  primigravidae; between 84% (OR 4.4[95% CI 2.0-9.6]) and 87% (OR 5.3[95% CI 1.1-24.7]) in  multiparous. Another significant predictor of successful induction of labour was the pre-induction Bishop’s score; 85.2% (OR 3.8[95% CI 1.6- 8.6]) of patients with Bishop score above 6 compared to 60.4% of patients with lower scores. The odds of a successful induction were also significantly lower in newborns weighing above 4000 grams (OR = 0.02, 95% CI 0.003-0.21) compared to those weighing less than 4000 grams.

Conclusion: A favourable Bishop’s score, multi-parity and birthweight were better predictors of  successful induction of labour in post term pregnancies at the KNH.

Keywords: Post-term pregnancy, Prolonged pregnancy, Induction of labour, Successful induction of labour