Risk factors for development of diabetes mellitus in women with a history of gestational diabetes mellitus

Objective To determine whether diabetes recurs in their later life when women have a history of gestational diabetes mellitus (GDM) or abnormal glucose tolerance test (impaired glucose tolerance, IGT).
Methods Three groups of women were investigated at 5-10 years postpartum. GDM group (n=45) had been diagnosed as having GDM in their previous pregnancy. IGT group (n=31) had a history of abnormal glucose tolerance test during previous pregnancy. Normal control group (n=39) was normal previous pregnant population. Their previous obstetric and medical histories were thoroughly reviewed. Fasting plasma glucose (FPG) and oral glucose (75 g) tolerance test (OGTT) were repeated in all women.
Results Diabetes mellitus (DM) was diagnosed in 33.3% of patients in the GDM group, while in 9.7% in the IGT group and in 2.6% in the normal control group. Incidence of recurring DM in later life was significant higher in the GDM group (P=0.017). When one or more blood glucose values exceeding WHO criteria for diagnosis of diabetes in their previous pregnancy, the incidence of DM in later life was 60% (3/5, including GDM in women having four abnormal OGTT values), 41.7% (5/12) in women having three, 25% (7/28) in women having two and 9.7% (3/31) in women having one. The women with DM, also with a history of GDM and abnormal OGTT in previous pregnancy, tends to have a high pregnant body mass index (BMI >25 kg/m²).
Conclusion The women suffering from GDM during previous pregnancy have a high risk of recurrence DM. Two or more abnormal OGTT values during pregnancy, blood glucose level exceeding the maximal values at 1 and 2 hours after oral glucose loading and high pregnant BMI are concluded to be useful factors in predicting the recurring DM in their later life.