Type 1 (insulin-dependent) diabetes mellitus diagnosed during pregnancy: a clinical and prognostic study.

The study concerns the clinical outcome and later prognosis (regarding permanent insulin treatment) of patients who develop insulin-dependent diabetes mellitus during pregnancy (which is different from gestational diabetes). Sixty-three such patients (27 +/- 1 (SEM) years old) were delivered at the Copenhagen Centre for Diabetes and Pregnancy during the years 1966-1980. Obstetric complications such as toxaemia were seen in 9.5% of these study patients and the perinatal mortality was 6.3%, both percentages being higher than in the general population (1.1%, p less than 10(-7) and 1.0%, p less than 10(-3), respectively), but similar to those observed in patients with Type 1 diabetes diagnosed before pregnancy. In contrast, the frequency of malformations was 1.6%, the same as in the general population (1.4%), but lower than that seen in patients with long-standing diabetes (8.3%, p less than 0.05). At follow-up examination 8 +/- 1 years after diagnosis all patients were diabetic; 77% were insulin treated, having no or virtually no residual B-cell function, and were clearly Type 1 diabetic patients. After delivery 80% of the patients had a remission period (median 256 days) without insulin treatment. This remission period was absent or shortest in patients with the following characteristics (p less than or equal to 0.03): low age, first parity, not overweight, and high blood glucose level at diagnosis. These prognostic parameters should be considered in obligatory, clinical follow-up plans for such patients.