Is epidural analgesia a risk factor for occiput posterior or transverse positions during labour?

The aim of this study was to assess whether the station of the fetal head at epidural placement is associated with the risk of malposition during labour.

Retrospective study (covering a 3-month period) of patients in labour with singleton cephalic term fetuses and epidural placement before 5 cm of dilatation. We studied the following risk factors for malposition: station and cervical dilatation at epidural placement, induction of labour, parity and macrosomia. Malposition, defined as all occiput posterior and occiput transverse positions, was assessed at 5 cm of dilatation because of our policy of systematic manual rotation for malpositions.

The study included 398 patients, 200 of whom had malpositions diagnosed at 5 cm of dilatation. In both the univariate and multivariate analyses, station at epidural placement was the only risk factor significantly associated with this malposition (adjusted OR: 2.49, 95% CI 1.47-4.24). None of the other factors studied was significantly associated with malposition: nulliparity (OR 1.45, 95% CI 0.96-2.20), macrosomia (OR 0.75, 95% CI 0.37-1.50), induction of labour (OR 0.84, 95% CI 0.49-1.45), or dilatation less than 3 cm at epidural administration (OR 1.16, 95% CI 0.59-2.30). Only three infants of the 365 delivered vaginally (0.8%) were born in occiput posterior positions.

Epidural placement when the fetal head is still "high" is associated with an increased rate of occiput posterior and transverse malpositions during labour.