Association between HbA1c levels on adverse pregnancy outcomes during pregnancy in type 1 diabetic patients.

CONTEXT Despite optimization of metabolic balance during pregnancy in type 1 diabetes (T1D), maternal-fetal complications remain higher than in the background population. We examined whether there is an association between HbA1c levels and these complications. METHODS Retrospective study of pregnancies in 678 T1D subjects at Lille Hospital (1997-2019). The association between variations in HbA1c levels and complications was examined. The composite criterion (CC) was defined as having at least one of the following complications: prematurity, preeclampsia, Large for Gestational Age (LGA), Small for Gestational Age (SGA) or cesarean section. RESULTS Among the 678 births, median pre-conception HbA1c was 7.2% (55mmol/mol), 361 were LGA (56%), 29 were SGA (4.5%) and 504 were births without preterm delivery (76.1%). The CC occurred in 81.8%. Higher HbA1c during the first trimester was associated with the CC (Odds-ratio (OR), 1.04 [95% confidence interval (CI), 1.02 to 1.06] per 0.1% increase; p 6.5% (48 mmol/mol) and a 3 rd trimester HbA1c <6% was associated with an increased rate of the CC (OR, 2.81 [95% CI, 1.01 to 7.86]) and an increased rate of LGA (OR, 2.20 [95% CI, 1.01 to 4.78]). CONCLUSION Elevated HbA1c is associated with maternal fetal complications. Despite optimization of metabolic balance during the 3rd trimester, for patients with early glycemic imbalance the risk of LGA persists.