ANTEPARTUM RISKS OF SHOULDER DYSTOCIA AND BRACHIAL-PLEXUS INJURY FOR INFANTS WEIGHING 4,200 G OR MORE

A cohort of 236 vaginally delivered neonates weighing greater than or equal to 4,200 g was evaluated. Shoulder dystocia was encountered in 2 7 deliveries (11.4%) and brachial plexus injury was diagnosed in 3 inf ants (1.3%). The 'traditional' antepartum risk factors could not be as sociated with shoulder dystocia. In this cohort, primiparity was signi ficantly more frequent among the dystocia cases (OR = 8.58, 99% CI = 1 .35-54.35, p = 0.021). Shoulder dystocia could not be attributed to a particular difference between the current and the previous heaviest bi rth weight. A policy of cesarean section for all infants weighing grea ter than or equal to 4,200 g would result in at least 5- to 6-fold inc rease in cesarean rate in this group of patients. Our data reconfirm t hat shoulder dystocia and brachial plexus injury are unpredictable, ev en in macrosomic infants. It is a matter of policy whether to accept t he expected 1:9 and 1:79 respective risks associated with vaginal birt hs.