Risk factors for unplanned cesarean delivery among pregnant individuals with pre-existing diabetes.

BACKGROUND: Diabetes in pregnancy is associated with an increased risk of cesarean delivery, including unplanned or emergency cesarean delivery. It is unclear which risk factors confer increased risk of cesarean among pregnancies with Type 2 diabetes or early gestational diabetes. Given the increased maternal risks associated with cesarean delivery, a better understanding of risk factors for unplanned cesarean delivery may improve patient care and reduce delivery complications among this high-risk population. OBJECTIVE: The objective of this study was to identify risk factors for unplanned primary cesarean delivery among pregnant individuals with Type 2 diabetes or diabetes diagnosed early in pregnancy. STUDY DESIGN: This was a secondary analysis of the Medical Optimization and Management of Pregnancies with Overt Type 2 Diabetes (MOMPOD) randomized controlled trial. Participants with pre-existing Type 2 diabetes or diabetes identified prior to 23 weeks were included if they had a trial of labor. Baseline and pregnancy characteristics were compared between those with a vaginal delivery and those with an unplanned cesarean delivery using descriptive and logistic regression analyses, controlling for potential confounders. RESULTS: Of 794 enrolled participants, 405 met prespecified inclusion criteria for this secondary analysis; of these, 144 (36%) had an unplanned cesarean delivery and 261 (64%) had a vaginal delivery. Indications for cesarean delivery were failed induction of labor (65/144; 45%), fetal intolerance to labor (51/144; 35%), and cephalopelvic disproportion or failure to progress (34/144; 24%). Compared to those with a vaginal delivery, participants with an unplanned cesarean delivery had greater median gestational weight gain (11.6 kg [interquartile range, IQR 6.8-15.4] vs. 10 kg [IQR, 4.4-14.9], p = 0.019), enrollment HbA1c ≥ 6.5% (69% vs. 56%, p = 0.0239), third trimester HbA1c ≥ 6.5% (39% vs. 25%, p = 0.0459), and higher median glucose levels in labor (130.0 mg/dL [IQR 112.0-161.5] vs. 121.0 mg/dL [IQR 100.0-144.0], p = 0.0025). There were no differences in the timing of diabetes diagnosis, metformin use, or birthweight between groups. In multivariable adjusted analysis controlling for nulliparity, Hispanic origin, marital status, pre-existing hypertension requiring medication, preeclampsia, and cigarette use in pregnancy, enrollment HbA1c (mean gestational age 11.2 weeks) (median HbA1c: 7.3% for CD vs. 6.85% for vaginal delivery; aOR 1.27 [95% confidence interval, CI 1.10, 1.46]), HbA1c ≥ 6.5% at enrollment (69% for cesarean delivery vs. 56% for vaginal delivery; aOR 2.26 [95% CI 1.28, 3.98]), HbA1c ≥ 6.5% in the third trimester (39% for cesarean delivery vs. 25% for vaginal delivery; aOR 2.78 [95% CI 1.21, 6.39]), and induction (88% for cesarean delivery vs. 76% for vaginal delivery; aOR 2.12 [95% CI 1.08, 4.17]) were associated with unplanned cesarean delivery. There was no difference in gestational weight gain or the highest glucose level in labor between groups. CONCLUSIONS: In patients with Type 2 diabetes or diabetes diagnosed in early pregnancy who are attempting vaginal delivery, early pregnancy HbA1c, third trimester HbA1c, and induction of labor are associated with an increased risk of unplanned primary cesarean delivery. Preconception counseling should focus on improved glycemic management prior to and in early pregnancy as a potential strategy to reduce the risk of unplanned cesarean delivery for pregnant individuals with pre-existing diabetes or diabetes diagnosed in early pregnancy.