We have some questions and comments on the interesting article by Inglis et al. Did their protocol permit initial gentle downward traction as required by the American College of Obstetricians and Gynecologists and the Royal College of Obstetricians and Gynaecologists definition?

The elephant in the room is the cesarean rate rising from pretraining 29.90% to an astonishingly high posttraining 40.14%, an increase of 34.2% over a 3-year time period. It is our opinion that this large increase in the authors’ cesarean rate would be a substantial factor in causing the decrease in obstetric brachial plexus injury (OBPI) in the posttraining period and should receive further discussion from the authors. Another factor would be the inordinately high pretraining shoulder dystocia–associated OBPI of 30% while the general literature reports around 10%, the same as the authors’ posttraining period.

Rouse et al reported a shoulder dystocia–associated rate of OBPI of only 18% and 26% for birth weights of 4000-4499 g and ≥4500 g, respectively, vs the author’s overall pretraining rate of 30%. The pretraining and posttraining cesarean rates for fetuses weighing >4000 g would be more revealing than the overall decrease in the average newborn weight of 182 g.

Rouse et al also reviewed 9 studies reporting a mean permanent OBPI of 6.7% of those with newborn OBPI. A total of 6.7% of 25 and 8 OBPIs, resulting from the pretraining and posttraining time periods, respectively, provides the actual number of permanent OBPIs of 1.7 and 0.5, or roughly 1 permanent OBPI prevented at a cost of 952 extra cesareans.

How do the authors explain “all OBPI cases were associated with shoulder dystocia,” which is contrary to the literature? There are 23 recent studies reporting approximately 50% of their cases of OBPI have no associated shoulder dystocia with their deliveries.

The authors’ remarkable posttraining reduction in OBPI is at variance with other authors (Mackenzie, Crofts and possibly Draycott – authors’ reference 15). Draycott et al did find fewer newborn OBPIs during the posttraining period but they were transient and did not persist during the ensuing 6 months of the newborn’s life.