Can we predict the likelihood of a successful vaginal breech birth?

How likely is a woman to have a cesarean when she is in labor with a breech baby? Is there any way to predict her chances of a vaginal birth based on how dilation and estimated fetal weight?

A teaching hospital in Liverpool compiled data on all singleton term and near-term breech babies born in their unit between 1988 and 1991. Nwosu et al (1993) calculated the likelihood of having an in-labor cesarean based on both estimated fetal weight and cervical dilation at admission. They explain:

Recently Chadha et al (1992) have shown that women admitted in labour with breech presentation at a low cervical dilatation (less than 3 cm) are more likely to be delivered by caesarean section. This is in agreement with our study. Using our results for all vaginal and emergency caesarean deliveries, we are able to tabulate the likelihood of caesarean section corresponding to various values of cervical dilatation on presentation and estimated fetal weight. These results are presented as Fig. 1 (Callygram), which could assist the clinician on the labour ward in counselling the woman, and in the choice of the best mode of delivery. It must be stressed that the tabulated (percentage) probabilities of caesarean section for given values of cervical dilatation and fetal weight are derived from our sample which has not specifically addressed the question of augmentation of labour [this unit did not induce or augment] and intrapartum external cephalic version (with or without tocolytics).

As you can see, the likelihood of a successful vaginal birth increases significantly with higher cervical dilation at hospital admission. EFW also plays a role, but that difference nearly disappears at both extremes of cervical dilation.

Cervical dilation at admission depends on how long the mother waits to go in, so this is a tricky thing to use as a predictive measure. There is no automatic set point at which women go to hospital (or, at home, call their midwife). A woman's likelihood of a vaginal breech birth also varies widely by hospital and by provider. But this does suggest that a rapidly progressing labor is a strong positive indicator of a successful vaginal breech birth.