Neonatal outcomes and rationale for timing of birth in perinatal diabetes: a retrospective cohort study

BACKGROUND: The American College of Obstetricians and Gynecologists recommends delivery in the 39th week of pregnancy for patients with pregestational and medication-controlled gestational diabetes with consideration for earlier delivery among those with poor glucose control. OBJECTIVE: We sought to evaluate the impact of birth before 39 weeks’ gestation exclusively for diabetes-related indications on neonatal outcomes and clinician rationale for these recommendations. STUDY DESIGN: This was a retrospective cohort study of all singleton, nonanomalous pregnancies complicated by diabetes. Patients were identified through an obstetrical database containing information of 90,185 births from 2011 to 2021. Patients who delivered in a given week of gestation exclusively for diabetes-related indications were compared with ongoing pregnancies. Recommended births for other obstetrical indications were excluded from the diabetes-related indications cohorts. The primary outcome was neonatal intensive care unit admission. Secondary outcomes included neonatal intensive care unit length of stay, stillbirth, neonatal death, hypoglycemia, respiratory distress syndrome, and shoulder dystocia. For all births before 39 weeks’ gestation, the electronic medical records were reviewed to confirm the rationale for the intervention for a diabetes-indicated condition. RESULTS: From the 90,185 recorded births that occurred in 2011 to 2021, 4750 patients with diabetes were identified. Of those, 30.5% (n=1449) had a recommended birth for a diabetes-related indications with 2.2% of those (n=32) occurring at 36 weeks’ gestation, 7.9% (n=114) at 37 weeks’ gestation, 9.7% (n=141) at 38 weeks’ gestation, and 63.0% (n=913) at 39 weeks’ gestation. Births that occurred at 36 and 37 weeks’ gestation exclusively for diabetes-related indications had higher rates of neonatal intensive care unit admission than the respective ongoing pregnancies (62.5% vs 8.7%; P<.001 and 25.4% vs 7.2%; P<.001). There was no difference in neonatal intensive care unit admission for births at 38 or 39 weeks’ gestation when compared with ongoing pregnancy. For neonates born at 36 and 37 weeks’ gestation in comparison with ongoing pregnancies, the median neonatal intensive care unit length of stay was 11.0 vs 2.8 days, (P<.001) and 4.4 vs 2.6 days (P=.026), respectively. There were significantly increased rates of neonatal hypoglycemia and respiratory distress syndrome among births that occurred at 36, 37, and 38 weeks’ gestation when compared with ongoing pregnancies. There were no differences in the rate of stillbirth in this cohort. Primary factors cited for early birth were poor glycemic control (71.4%), recommendation by a maternal-fetal medicine specialist (38.7%), and suspected fetal macrosomia (27.9%). Overall, 46.7%, 32.8%, and 20.6% of patients had 1, 2, or ≥3 indications, respectively, listed as rationale for early birth. Overall, few objective measures were used to recommend birth before 39 weeks’ gestation owing to diabetes. CONCLUSION: In pregnancies complicated by diabetes, early birth exclusively for diabetes-related indications was associated with increased neonatal intensive care unit admission and length of stay and with neonatal morbidity. Little objective data are documented by clinicians to support their recommendations for early birth associated with diabetes. Additional clinical guidelines are needed to define suboptimal glucose control necessitating birth before 39 weeks’ gestation.