The Effect of Delivery Timing on Cesarean Delivery Rate in Pregnancies Complicated by Pregestational Diabetes and Large-for-Gestational-Age Neonate.

OBJECTIVE

The Big Baby Trial found that early induction in patients with suspected large-for-gestational-age (LGA) fetuses reduced shoulder dystocia and prelabor cesarean rates. However, it excluded patients with pregestational diabetes mellitus (PGDM), who are at increased risk of adverse outcomes. We sought to evaluate delivery outcomes by gestational week in patients with PGDM and LGA fetuses.

STUDY

DESIGN

This was a population-based cohort study of nulliparous, nonanomalous, singleton, live births complicated by PGDM and LGA between 360/7 and 416/7 weeks using the U.S. Natality Vital Statistics Database from 2015 to 2023. Births following a prior cesarean delivery were excluded. Planned delivery group included births at each completed week from 36 to 40 weeks that underwent labor induction or scheduled cesarean delivery, excluding spontaneous labor. Expectant management group included all births that delivered in subsequent weeks (e.g., planned birth 360/7-366/7 compared with all births ≥370/7 weeks). The primary outcome was cesarean delivery rate and the secondary outcome was a composite of adverse neonatal outcomes (5-min Apgar score < 7, assisted neonatal ventilation > 6 hours, neonatal seizures, 10-min Apgar score of 0, and neonatal death). Outcomes were compared between groups at each week using multivariable logistic regression.

RESULTS

There were 9,805 births analyzed. Cesarean delivery rate ranged from 77 to 87%. After adjusting for baseline differences between groups, planned delivery at 39 weeks was associated with decreased odds of cesarean delivery than expectantly managed pregnancies. After 38 weeks, planned delivery and expectant management had similar odds of cesarean delivery and neonatal morbidity.

CONCLUSION

In pregnancies complicated by PGDM and LGA, planned delivery after 39 weeks was associated with lower odds of cesarean delivery compared with expectant management. Planned delivery at 38 weeks had similar odds of cesarean delivery and neonatal morbidity. These data suggest that providers should be cautious expectantly managing these pregnancies past 38 weeks.

KEY POINTS: · Pregnancies complicated by PGDM and LGA are associated with higher risk of cesarean delivery.. · Across all gestational ages, planned delivery group was more likely to deliver by cesarean delivery than those expectantly managed.. · Planned delivery after 39 weeks was associated with lower odds of cesarean delivery compared with expectant management.. · Planned delivery prior to 38 weeks (36-37 weeks) is associated with increased cesarean delivery rates and higher neonatal morbidity..