Evaluation of ultrasound cervical length and fetal fibronectin prior to induction of labour in nullipara: markers for labour induction success

Objective To determine the predictive value of the ultrasound cervical length, the fetal fibronectin test and their combination in the success of induction of labour in nulliparous women at term. Material and Methodology This is a prospective study conducted between September 2004 and May 2007. 60 nulliparous women booked for induction of labour were included. Cervical length was assessed by transvaginal ultrasound and a sample for fetal fibronectin was obtained prior to digital vaginal examination. Results The mean age of the examined women was 27.7 years (16–42 years). The overall Caesarean rate was 29.5%. The mean gestational age was 40+2 (38+4 −42). In 91% of these cases the cervix was unfavourable (Bishop score ≤5). Cervical length ranged from 14 to 49 mm (median 27.3 mm). In cases were the cervical length was ≤27 mm (54%) vaginal delivery was achieved within 24 h of induction in 80% (sensitivity 65%, specificity 60%). Women with positive fetal fibronectin result were more likely to deliver vaginally than those who had a negative result (sensitivity 73.3%, specificity 65%). Conclusion In nulliparous women ultrasound cervical length (UCL) and fetal fibronectin (fFn) are useful predictors for vaginal delivery. On the other hand Bishop Score cannot predict the mode of delivery. UCL and fFn were found to be independently associated with the total duration of labour. Bishop score failed to predict the total duration of labour.