(343) Term management of the suspected large for gestational age fetus

Our aim was to compare maternal and neonatal outcomes following labor induction versus expectant management of full-term suspected large-for-gestational-age (LGA) fetuses.

Study Design:

This population-based retrospective cohort study obtained data on births in Ontario, Canada (2012-2021) from the provincial perinatal registry linked to several health administrative databases via ICES. We included individuals with full-term, singleton pregnancies with suspected LGA and excluded those with contraindications to vaginal delivery. The exposure was labor induction for the primary indication of LGA compared with expectant management at each gestational week from 37–41 weeks of gestation. Outcomes included composite maternal (e.g., unplanned operative delivery, postpartum hemorrhage, obstetric trauma) and neonatal (e.g., shoulder dystocia, severe birth injuries, need for neonatal resuscitation) complications. Covariates such as maternal age, parity, body mass index, diabetes and socioeconomic factors were used to create propensity scores for the probability of experiencing induction. Overlap weighting of propensity scores was used in modified Poisson regression models.

Results:

Among 10,884 deliveries complicated by suspected LGA, induction rates increased from 1.5% at 37 weeks, to 26.8% at 41 weeks. The maternal composite outcome occurred in 46.2% and 46.5% of births with expectant management and induction, respectively, and increased with advancing gestation (Fig 1). The neonatal composite was stable across gestational weeks and occurred in 27.6% with expectant management and 26.4% with induction. While crude models suggested lower rates of maternal complications with induction (e.g. rate ratio [RR] at 39 weeks 0.90, 95% CI 0.85-0.95), adjusted models showed no association with composite maternal or neonatal complications, irrespective of gestational week (e.g. RR at 39 weeks 1.00, 95% CI 0.90-1.10; Fig 2).

Conclusion:

Induction of labor for suspected LGA among term pregnancies compared to expectant management did not change the risk of composite maternal or neonatal complications at any gestational week.