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