Obstetric brachial plexus palsy: a prospective study on risk factors related to manual assistance during the second stage of labor

Background. To evaluate the association between obstetric brachial plexus palsy and obstetrical maneuvers during the second stage of delivery. Methods. Prospective population-based case control study. Cases of obstetric brachial plexus palsy were compared with a randomly selected control group with regard to obstetric management. Results. Five or more obstetrical maneuvers were used to deliver the infants in 82% in the obstetric brachial plexus palsy group versus 1.8% in the controls. Risk factors independently associated with obstetric brachial plexus palsy were force applied when downward traction was imposed on the fetal head (odds ratio 15.2; 95% confidence interval 8.4-27.7). The incidence of obstetric brachial plexus palsy in the infants in the population was 3.3 parts per thousand. At 18 months of age 16.1% (incidence of 0.05%) of children had residual functional deficits and downward traction with substantial force was applied in all these cases. Conclusions. Forceful downward traction applied to the head after the fetal third rotation represents an important risk factor of obstetric brachial plexus palsy in vaginal deliveries in cephalic presentation.