Objective: Macrosomia at term is associated with increased maternal and neonatal morbidity, including a higher rate of cesarean delivery and shoulder dystocia. Induction of labor has been suggested as a means to prevent further weight gain and improve outcome. The aim of this study was to determine whether or not induction of labor in these cases improves maternal and neonatal outcome.
Methods: Patients at term with an ultrasonic fetal weight estimation of 4000-4500 g were prospectively randomized into two groups: induction of labor (group D and expectant management (group II). Patients with diabetes, a previous cesarean delivery, or nonvertex presentation were excluded. Outcome variables included mode of delivery, arterial cord pH, presence of shoulder dystocia, brachial plexus injury, clavicular fracture, cephalohematoma, and intraventricular hemorrhage.
Results: Of 273 patients who were eligible for the study, 134 were randomized to group I and 139 to group II. Parity, gestational age, and fetal weight estimation were similar in the two groups. The neonates of group II patients were significantly heavier (4132.8 +/- 347.4 versus 4062.8 +/- 306.9 g; P = .024). The rate of cesarean delivery was 19.4% in group I and 21.6% in group II patients (not significant [NS]). Cord pH was similar in both groups. Shoulder dystocia was diagnosed in five group I and six group II patients (NS). None developed brachial plexus injury. There were two cases of mild, transient brachial plexus injury in group II patients without documented shoulder dystocia. Mild intraventricular hemorrhage was diagnosed in three of 44 group I and two of 31 group II neonates evaluated (NS).
Conclusion: In this prospective, randomized study, induction of labor for suspected macrosomia at term did not decrease the rate of cesarean delivery or reduce neonatal morbidity. Ultrasonic estimation of fetal weight between 4000 and 4500 g should not be considered an indication for induction of labor.