Women who have higher than normal blood glucose levels during pregnancy, but which do not meet the defined criteria for gestational diabetes, are also at increased risk of type 2 diabetes later on, says a recent study published in The Lancet Diabetes & Endocrinology.¹

This study was conducted in 177,241 Israeli women who were assessed at age 16-20 years and later were screened using a 50 g glucose challenge test (GCT) with a cut-off level of 140 mg/dL and then a 100 g oral glucose tolerance test (OGTT) as needed. The threshold values for abnormal OGTT were ≥95 mg/dL fasting, ≥180 mg/dL at 1 hour, ≥155 mg/dL at 2 hours and ≥140 mg/dL at 3 hours. The aim of the study was to ascertain an association between gestational glucose intolerance and the risk of type 2 diabetes, which was the primary study outcome, in young adulthood over a median follow-up of 10.8 years.

A total of 1262 women were diagnosed with type 2 diabetes during the course of the study. Among women with normal blood glucose levels during pregnancy, the incidence of type 2 diabetes was 2.6 per 10 000 person-years. The incidence increased to 8.9 per 10 000 person-years in women with an abnormal GCT but a normal OGTT, whereas among women with one abnormal OGTT reading, the incidence rate jumped to 26.1 per 10 000 person-years and 71.9 per 10 000 person-years in those with gestational diabetes.

After adjusting for confounding factors, women with an abnormal GCT and normal OGTT were nearly 4 times more likely to develop type 2 diabetes with an adjusted hazard ratio of 3.39 compared to women with gestational normoglycemia. The risk was increased 9-folds in women with one abnormal OGTT value with adjusted HR of 9.11. Women who had had gestational diabetes were 24-times more at risk of type 2 diabetes with adjusted HR of 24.84.

Women who just had one-time high fasting glucose had an 11-fold higher risk of type 2 diabetes with adjusted HR of 11.81, whereas the HR among women with gestational diabetes and abnormal fasting glucose was 38.02.

Glucose intolerance in pregnancy, and not just gestational diabetes, is associated with an increased risk of early-onset type 2 diabetes below 40 years of age suggesting gestational glucose intolerance as a risk factor for type 2 diabetes. Women should be educated about the associated health risks, both short-term and long-term. Those who just had one abnormal glucose value were also at high risk of diabetes in this study and therefore these women too should be advised preventive lifestyle modifications. They may also be candidates for metformin treatment.

Reference

1. Aya Bardugo, et al. Glucose intolerance in pregnancy and risk of early-onset type 2 diabetes: a population-based cohort study. Lancet Diabetes Endocrinol. 2023 Mar 31;S2213-8587(23)00062-1. doi: 10.1016/S2213-8587(23)00062-1.