Comparison of sonographic measurement of cervical length with Bishop Score to predict success rate of labor induction

INTRODUCTION: Labor induction is imperative for 20-30% of all pregnancies, and is related to increased rate of C-section. In order to predict likelihood of the induction, cervix is evaluated manually and sonographically and Bishop Score is commonly preferred.
METHODS: 126 singleton pregnancies of 37-41 weeks, with cephalic presentation and no histrory of uterine surgery, were selected for birth induciton and included in this prospective obervational study. Age, gestational week, indication of birth induction, gravidity and parity, estimated fetal weight, delivery method, bishop socre, sonographicly measured cervical length were recorded.
RESULTS: C-section rate (%54.8) and vaginal delivery rates (%89.4) were higher in groups with bishop score less than 5 and greater than 5 respectively, Bishop score is a statistically significant method to foresee birth induction success. (p<0,001). Parity and delivery method were statistically significant in groups with different bishop score. In terms of cervical length with 25 mm cut off, vaginal delivery was dominant in both groups, (%69,6 and 59,6 respectively) and there was no significant difference between these groups. (p>0,05). Parity and vaginal delivery rates were similar in both groups of cervival length. In gap analysis there was no significant difference between 2 groups. With a cut off point of 25 mm, sensitivity of specificty of cerival length were reported as 52.3% and 58.5% respectively.
DISCUSSION AND CONCLUSION: Bishop score and parity were favorable predictors; whereas sonographic measurement of cervical length is an inadequate parameter to infer success rate of birth induction.