Dr. Bryant et al., LIMITED USEFULNESS OF FETAL WEIGHT IN PREDICTING NEONATAL BRACHIAL-PLEXUS INJURY, American journal of obstetrics and gynecology, 179(3), 1998, pp. 686-689
OBJECTIVE: The objectives were to determine the neonatal morbidity rat
e from vaginal birth and examine fetal weight-based injury-prevention
strategies. STUDY DESIGN: Selected neonatal morbidities were categoriz
ed by birth weight for all vertex vaginal deliveries occurring during
a 12-year period. Sensitivity, specificity, and predictive values for
brachial palsy were calculated at increasing birth weight cutoff level
s. A policy of cesarean delivery far macrosomic infants was evaluated.
RESULTS: There were 80 cases of brachial palsy among 63,761 infants (
0.13%). In mothers without diabetes, rates in the 4500- to 4999-g and
>5000-g groups were 3.0% and 6.7%, respectively. A threshold of 3700 g
had a sensitivity of 71% and a specificity of 86%; the positive predi
ctive value was 0.56%. To prevent a single case of permanent injury, 1
55 to 588 cesarean deliveries are required at the currently recommende
d cutoff weight of 4500 g. CONCLUSIONS: The rates of lasting morbidity
do not justify routine cesarean delivery for infants without diabetic
complications weighing <5000 g.