Factors associated with delivery at <39 weeks for "poor glucose control" in perinatal diabetes

ACOG guidelines recommend delivery in the 39th week of pregnancy for patients with pre-gestational and medication-controlled gestational diabetes but allow for consideration of delivery < 39 weeks in the setting of “poorly controlled” diabetes. Unfortunately, “poor control” is not explicitly defined. We examined diabetes-related criteria that clinicians use to justify early delivery. This is a descriptive analysis of all pregnancies with diabetes from 2011-2021 within a multi-institution health system. Patients delivering < 39 weeks with only a diabetes-related indication for delivery were identified. Any reported glucose values for those patients were reviewed. For the purposes of this study, we pragmatically defined “poor glucose control” as >50% of recorded glucose values within two weeks prior to delivery outside of the expected range. Hemoglobin A1C (HbA1c) within 3 months of delivery was also identified. We assessed clinician rationale for delivery via review of notes at or before hospital admission. Chi-square and Fisher’s exact tests were used for statistical analyses. We identified 4750 patients with perinatal diabetes: 287 patients delivered at < 39 weeks for a diabetes-related indication. 32% had a HbA1c within 3 months of delivery with median values of 7.2%, 5.9%, and 5.8% for patients delivering at 36, 37 and 38 weeks, respectively. 61% had glucose values documented in the medical record: just 21% of patients met our pragmatic definition of “poor glucose control”. However, 71% were described by a provider as having “poor glucose control” and underwent early delivery solely for this reason. The next most common indications for early delivery were “recommendation by a Maternal Fetal Medicine specialist” (39%) and “suspected fetal macrosomia” (28%). 21% had ≥3 factors listed as delivery indications (Table 1). Overall, little objective data underlies clinicians’ decision to recommend early delivery for “poor glucose control”. Additional guidelines are urgently needed to objectively define “poor control” and standardize delivery recommendations.