HLA associations in insulin-dependent diabetes mellitus diagnosed during pregnancy.

Sixty out of 63 patients with insulin-dependent diabetes mellitus (IDDM) diagnosed during pregnancy in the Diabetes Centre at the Department of Obstetrics and Gynaecology, Rigshospitalet, Copenhagen, were re-examined 2-16 years after diagnosis. Fourty-six patients were currently insulin-treated and the remaining 14 patients were all severely glucose intolerant. HLA-typing was carried out in 41 of these patients. The HLA phenotype distribution showed a highly significant difference from that of non-diabetics but was similar to that seen in IDDM not related to pregnancy. Thus, pregnancy may constitute a special trigger mechanism for IDDM, but the subsequent pathogenic mechanisms are probably the same as those involved in other cases of IDDM.