Background:
Gestational diabetes mellitus (GDM) is increasingly prevalent in Australia, affecting 18% of pregnancies. Recent research suggests GDM is heterogeneous, yet management remains largely uniform. This study evaluated whether the number and type of abnormal oral glucose tolerance test (OGTT) values in pregnancy are associated with increased postpartum cardiometabolic risk.
Methods:
This is a retrospective registry analysis of 295 women with GDM who attended a 6-month postpartum lifestyle clinic at Lyell McEwin Hospital from 2018-2024. Participants were stratified by the number of abnormal OGTT values (1, 2 or 3) and by OGTT profile: isolated fasting hyperglycaemia (IFH), isolated post-load hyperglycaemia (IPH), or combined hyperglycaemia (CH). Biochemical and anthropometric data at 6 months postpartum was used to assess cardiometabolic risk, specifically prevalence of type 2 diabetes and metabolic syndrome.
Results:
Of 295 women, 56% had 1 abnormal OGTT value, 28% had 2, and 16% had 3. Mean postpartum fasting glucose was highest in women with 3 abnormal values (5.8 mmol/L) versus 1 (5.2 mmol/L) (p<0.001). Prevalence of type 2 diabetes at 6 months was higher in those with 3 abnormal values (14.6%) compared to 1 (1.2%) (p<0.001). Metabolic syndrome prevalence was 35% (1 value), 41% (2 values) and 63% (3 values) (p<0.008). Women with CH had higher postpartum fasting glucose (5.6 mmol/L) (p<0.001) and triglycerides (1.7 mmol/L) (p<0.022) than IFH or IPH.
Conclusion:
Greater OGTT abnormalities in pregnancy are associated with higher postpartum dysglycaemia, metabolic syndrome and type 2 diabetes. OGTT profiling may help tailor intrapartum and postpartum risk counselling and intervention.