Does ultrasonographic foetal head position prior to induction of labour predict the outcome of delivery?

OBJECTIVE: To examine the capacity of pre-induction sonographic assessment of occipital position of the foetal head to predict the outcome of delivery, and to assess whether sonographic foetal head position before induction of labour is related to foetal presentation at delivery.

STUDY DESIGN: A prospective cohort study was conducted in the Máxima Medical Centre, The Netherlands. We included consecutive women in whom labour was induced. Immediately prior to induction a transabdominal ultrasound was performed to determine the position of the foetal occiput. The primary outcome was mode of delivery. We recorded maternal demographics, labour and delivery characteristics, maternal and neonatal outcomes. The association between position of the foetal head before induction of labour and the occurrence of caesarean section was addressed using univariable and logistic regression analysis.

RESULTS: From the 50 of the 183 foetuses that started labour in occipitoposterior position, 11 persisted in occipitoposterior position until birth, whereas from the 120 foetuses that were in occipitoanterior position before induction, three children were born in an occipitoposterior position. Although we found a difference in caesarean section rate between OP position and OA position of the foetal head at sonography prior to induction, this was not statistically significant (14% versus 6.7%, OR 2.3, 95% CI 0.78-6.7).

CONCLUSION: Our study demonstrates that OP position prior to labour induction does not affect mode of delivery. Sonographic assessment of the position of the foetal head prior to labour induction should not be introduced in clinical practice.