Impact of induction of labor in fetal macrosomia: comparative series from 256 cases

The management of fetal macrosomia remains controversial. A protocol for induction of labor in the case of a suspected macrosomic fetus has been in place in our maternity hospital since 2016. We studied the impact of this protocol by analyzing the mode of delivery. We then studied its safety in terms of maternal and fetal morbidity and mortality and the risk factors of macrosomia.

Retrospective, comparative, single-center study including 256 patients between 2016 and 2020 in a type 3 maternity hospital in France. We compared 114 patients induced at 39 weeks of gestation (fetal weight ≥ 95th p; group 1) with 142 patients who after 37 weeks of gestation delivered a macrosomic newborn (≥ 95th p according to Audipog; group 2) not diagnosed antenatally.

The rate of vaginal delivery in the group 1 was 78.9% vs 83.8% in group 2 (p = 0.318). The rate of neonatal acidosis in group 1 was statistically lower than in group 2 (5.2% vs 16.9%; p = 0.004). The other maternal and neonatal outcomes were not significantly different in the two groups. A previous macrosomic newborn appeared to be a risk factor for macrosomia (p = 0.02).

The establishment of a protocol for the induction of labor in the case of macrosomia in our maternity hospital did not increase the rate of vaginal delivery, but has a neonatal benefit, by significantly reducing neonatal acidosis.