(238) Optimal timing of delivery in pregnancies complicated by pregestational diabetes: a population-based study

The American College of Obstetricians and Gynecologists recommend delivery 36 0/7-39 6/7 weeks for pregnancies complicated with pregestational diabetes mellitus (PGDM) based on limited data. Our objective was to assess neonatal and maternal morbidity at birth for each week of gestation in pregnancies complicated with PGDM to determine risk versus benefit between 36 0/7-39 6/7 weeks. 

Study Design:

This was a population-based cohort study of non-anomalous, singleton, live births complicated by PGDM between 36 and 41 completed weeks using data from the U.S. Natality Vital Statistics (2015-2021). Planned delivery group were births at each completed week from 36 to 39 weeks that had a labor induction or pre-labor cesarean delivery, excluding spontaneous labor. Expectant management group included all births that delivered on or after the following week (i.e., planned birth at 36 0/7-36 6/7 was compared to all births ≥ 37 0/7 weeks). The primary outcomes were neonatal and maternal adverse composites (Figure 1). These outcomes were compared between both groups at each week using multivariable analyses. 

Results:

There were 173,822 births. Before 38 weeks, planned delivery had higher odds of neonatal morbidity than those expectantly managed (planned 36 weeks births: 7.5% vs expectant births ≥37 weeks: 2.9%, aOR 1.81, 95% CI 1.61-2.04; planned 37 weeks birth: 4.1% vs expectant births ≥38 weeks: 2.3%, aOR 1.34, 95% CI 1.21-1.48). Planned delivery at 38 weeks and 39 weeks had lower odds of neonatal morbidity than those expectantly managed (38 weeks: 2.3% vs ≥39 weeks 2.1%, aOR 0.88, 95% CI 0.77-0.99; 39 weeks: 1.7% vs ≥40 weeks: 2.3, aOR 0.71, 95% CI 0.61-0.83). Planned delivery at ≥38 weeks had similar odds of maternal morbidity to those expectantly managed.

Conclusion:

For pregnancies complicated with PGDM, planned delivery at 38 0/7-39 6/7 weeks had lower odds of neonatal morbidity and no difference in maternal morbidity compared to expectant management. This data suggests optimal delivery timing for pregnancies with PGDM is 38 0/7-39 6/7 weeks. A randomized trial is needed to confirm this finding.