2: Induction of labor or expectant management for large-for-dates fetuses: a randomized controlled trial

Abstract

To compare induction of labor with expectant management for large for dates fetuses to prevent macrosomia at birth, shoulder dystocia and the associated neonatal morbidity. We conducted a randomized controlled trial in collaboration with 20 teaching hospitals, members of the GROG group, in France, Switzerland and Belgium. We included 817 women with a fetus with an estimated weight above the 95th percentile at 37 to 38 weeks of gestation. Women with diabetes treated with insulin and past history of cesarean section or shoulder dystocia were not included. The screening was first performed clinically (estimated weight above the 90th percentile), then a sonography was performed. Women were eligible if the sonographic estimated weight was above the 95th percentile. Women were randomized to induction of labor within 3 days (n=407) or expectant management (n=410). The primary outcome measure was neonatal trauma, including significant shoulder dystocia (defined as resolved by maneuvers other than McRoberts), fracture of the clavicle and brachial plexus injury, or perinatal death. Baseline characteristics were similar between groups. A difference in mean birthweight of nearly 300 gr between groups was obtained (3831 gr versus 4112 gr). The risk of neonatal trauma was reduced with induction of labor (n=9, 2.2%), compared to expectant management (n=27, 6.6%) (RR: 0.34; 95%CI: 0.16 to 0.71). The likelihood of a spontaneous vaginal delivery was higher (RR 1.14; 95%CI: 1.00 to 1.29) in the induction of labor group. The risk of cesarean section was not increased after induction of labor (28.0% vs 31.7% in the induction and expectant groups, respectively). Other neonatal morbidities were similar between groups, with no recorded cases of wet lung, brachial plexus palsy and perinatal death. Induction of labor in case of suspected large for dates fetus is associated with a lower risk of trauma at birth. This intervention does not result in an increased risk of cesarean section and improve the likelihood of a spontaneous vaginal delivery.