Should we conduct a trial of labor in women with a macrosomic fetus?

OBJECTIVES

There is much debate about the best mode of delivery for the macrosomic fetus. This study compares maternal and neonatal outcomes of macrosomic in prelabor cesareans (PLC) vs. in trials of labor (TOL).

METHODS

Retrospective cohort including neonates with birthweight of 4,000 g or more delivered in a public teaching hospital between October 2019 and December 2024. Exclusions: preterm, non cephalic, multiples, fetal death and malformed. Created three composite outcomes: "any serious adverse neonatal outcome", "any adverse maternal outcome", "neonatal respiratory morbidity". Considered significant a value of p<0.05.

RESULTS

Included 611 births. There was no maternal death and, in the group of TOL, one neonatal death; 37.7 % had vaginal births and 62.3 % had cesareans. Were conducted 341 (56 %) TOL's; from these, 32.8 % failed. Among 231 vaginal births, we had 61 (26.4 %) cases of shoulder dystocia, among which 9 neonates were discharged with brachial plexus injury (3.9 % of vaginal births; 1/25). We found a greater frequency of "any neonatal adverse outcome" in TOL, adjusted Odss Ratio (aOR) 6.68; p=0.037. No significant difference in "respiratory morbidity". In TOL, the frequency of "any maternal adverse outcome" was higher: aOR 3.53; p=0.009. A sensivity analysis excluding birthweights of 4,500 g or more had basically the same results.

CONCLUSIONS

We had a high frequency of infants discharged with brachial plexus injury. Higher maternal morbidity in TOL could be because of the high rate of failed TOL. Not accessed in this work, there is still some difficulty in correctly identifiying the macrosomic antenatally.