Adequacy of glycemic control in early pregnancy with Type 2 diabetes and perinatal outcomes

Abstract

Objective In non-pregnant individuals with type 2 DM (T2DM), an HbA1c target < 7% is recommended. We sought to assess if an HbA1c < 7% in early pregnancy is associated with a lower risk for adverse pregnancy outcomes.

Study Design We conducted a retrospective cohort study of individuals with T2DM and a singleton gestation who delivered at 2 health systems between 2018-2020. Demographics, markers of health care utilization, and perinatal outcomes were abstracted from the medical record. Race and ethnicity were self-reported. The primary exposure was levels of glycemic control at less than 20 weeks’ gestation using recommended HbA1c targets in non-pregnant individuals (HbA1c < 7% vs. HbA1c ≥7%). Patients without documentation of HbA1c prior to 20 weeks were excluded. Perinatal outcomes were abstracted from the medical record, and logistic regression was used to adjust for covariates.

Results Of the individuals who had a documented HbA1c < 20 weeks of gestation, 128/281 (46%) had a HbA1c < 7%, and 153/281 (54%) had a HbA1c ≥7%. Patients with HbA1c < 7% were more likely to be of White race and have private insurance. They also had the first HbA1c measured earlier in pregnancy, a lower mean HbA1c across gestation, less overall weight gain, and were less likely to require insulin at the time of delivery. There were no significant differences in other demographics or markers of healthcare utilization (Table 1). Outcomes are shown in Table 2. After adjusting for covariates, those with a HbA1c ≥7% were more likely to have a preterm birth < 37 weeks (aOR 2.3, 95% CI 1.3-4.0), cesarean delivery (aOR 1.9, 95% CI 1.1-3.3), and a neonate requiring NICU admission (aOR 2.9, 95% CI 1.7-4.9).

Conclusion Adverse perinatal outcomes are common among individuals with T2DM even when early pregnancy HbA1c values are within recommended targets for non-pregnant individuals. Those who present with a HbA1c ≥7% are at even higher risk for several outcomes. We observed important disparities in HbA1c values in early pregnancy that likely represent barriers in accessing medical care prior to pregnancy.