Rapid Postpartum Progression to Diabetes Following Early Antenatal Prediabetes: Evidence From a Multiethnic New Zealand Cohort.

OBJECTIVE

We compare the risk of postpartum diabetes in people with early antenatal prediabetes, HbA1c 5.9-6.4% (41-47 mmol/mol), versus those with HbA1c <5.9% (41 mmol/mol) who developed gestational diabetes mellitus (GDM) in later pregnancy. Secondly, we perform an exploratory analysis of lipid profiling to guide antenatal and postpartum management decisions for people with antenatal prediabetes.

RESEARCH DESIGN AND

METHODS

We analyze a prospective cohort study conducted in New Zealand. The "antenatal prediabetes" group was identified during 2017-2022 (n = 355). The comparator "GDM" group was identified in 2017 (n = 490). Postpartum laboratory data were collected from electronic health records until November 2025. Progression to diabetes was evaluated using multivariate analysis.

RESULTS

Compared with GDM, adjusted hazard ratios for postpartum type 2 diabetes following antenatal prediabetes were 4.5 (2.8-7.3) to 16.7 (10.8-25.8) for HbA1c 5.9% (41 mmol/mol) to 6.2-6.4% (44-47 mmol/mol), P < 0.001. HbA1c was the strongest predictor of type 2 diabetes, followed by BMI and Pacific ethnicity. Lipid profiles in the antenatal prediabetes cohort varied according to postpartum diagnosis: glucokinase monogenic diabetes was associated with lower serum triglycerides, mean 53.1 mg/dL (0.6 mmol/L), versus type 2 diabetes, 183.4 mg/dL (2.07 mmol/L), P = 0.012, or versus no diabetes, 165.6 mg/dL (1.87 mmol/L), P = 0.013; in type 1 diabetes, mean triglycerides were 87.7 mg/dL (0.99 mmol/L).

CONCLUSIONS

Early antenatal prediabetes is a strong predictor of rapid progression to type 2 diabetes. HbA1c at booking provides an important risk stratification tool identifying people with the greatest need for preventive intervention. Further research could evaluate lipid profiling to identify genetic and autoimmune diabetes subtypes within antenatal prediabetes.