783 Macrosomic newborns in pregnancies with diabetes: labor versus prelabor cesarean delivery

Abstract

ACOG recommends prelabor cesarean delivery (CD) at a threshold of 4,500g for individuals with diabetes, but makes no distinction between pregestational diabetes (pre-DM) and gestational diabetes (GDM). Our objective was to compare adverse outcomes associated with prelabor CD, versus attempted vaginal delivery, in pregnancies complicated by pre-DM or GDM. This population based cross-sectional study utilized the US period linked birth-infant death data (2014-2018). We included cephalic, non-anomalous, singleton live-born infants with diabetes at 37-41 weeks. A propensity score analysis was performed by matching individuals who underwent prelabor CD with those who attempted labor. Birthweight (BW) was grouped as: 3,500-3,999g, 4,000-4,499g, and 4,500-5,999g. Pregnancies were matched by BW and diabetes type into 6 cohorts. The co-primary outcomes were composites of neonatal (CNAO) and maternal (CMAO) adverse outcomes. The association between prelabor CD, CNAO and CMAO was examined within each cohort using conditional logistic regression. Through a probabilistic bias analysis, odds ratios were simultaneously corrected for potential differential outcome misclassification of CNAO and CMAO, selection bias, and unmeasured confounding. Of the 19 million births, 322,304 (1.6%) met inclusion criteria. Greater than 80% matching was achieved in all BW cohorts. CNAO and CMAO were higher with prelabor CD with BW 3,500-3,999g in both groups. CMAO was higher with prelabor CD and BW 4,000-4,499g in pregnancies with pre-DM (OR 3.57, 95% CI 1.37-9.48), but lower in pregnancies with GDM (OR 0.57, 95% CI 0.36-0.86). CNAO and CMAO trended lower with prelabor CD when BW exceeded 4,500g in both pre-DM and GDM groups (Tables 1-2). Following robust adjustments for confounders as well as adjustments for biases due to misclassification, selection, and unmeasured confounding, prelabor CD was associated with a trend toward improved outcomes for the maternal-neonatal dyad with BW ≥4,000g in pregnancies with GDM and BW ≥4,500g in pregnancies with pre-DM.