P30.11: Ultrasound assessment of cervical length in labour induction: prediction of maternal and perinatal outcome

Abstract

To evaluate the usefulness of sonographic assessment of cervical length in the prediction of maternal and perinatal outcome at the beginning of labour induction. We performed a prospective cohort study of 165 inductions of labor. Indications of labor induction were prolonged pregnancy (53.9%), pre-eclampsia (13.3%), fetal growth restriction (10.9%), gestational diabetes (9.7%), and others (12.2%). When the Bishop score was below 6 at admission, cervical ripening with prostaglandins was performed. Membrane rupture and intravenous oxytocin was used in all cases. Maternal and perinatal variables were collected prospectively. Analisys was performed by logistic regression analysis and ROC curves. The rate of cesarean delivery after induction was 23.6%, 46.7% of patients were nulliparous, and 16.7% of patients had a history of previous cesarean section. Mean gestational age at the inclusion was 39.7(1.6) weeks. Ultrasound cervical length areas under the ROC curve for prediction of Cesarean section were 75% (95% CI 62–83%; P = 0.04), and for the prediction of severe maternal complication 83% (95% CI 74–92%; P = 0.007). Cervical length of 20 mm was the best cut-off for the prediction of cesarean after labor induction (92% sensitivity and 68% specificity). Patients with a cervical length < 20 mm at the beginning of labour induction had a lower rate of cesarean sections (10.7% vs. 33.7%; P = 0.018) (OR 0.19 (CI 95% 0.05–0.76; P = 0.02)) and cesarean section for failed induction (7.1% vs. 24.7%; P = 0.045) (OR 0.16 (CI 95% 0.03–0.75; P = 0.03)) and a trend to reduced neonatal admission rate (3.6% vs. 15.1%; P = 0.101), umbilical artery pH below 7.20 (7.4% vs. 17.4%; P = 0.184) and severe maternal complications (0% vs. 7%; P = 0.151). Ultrasonographic measurement of cervical length at labour induction admission predicts maternal and perinatal outcome and the risk of Cesarean section.