Gestational Diabetes May Predict Autoimmune Diabetes Risk

It can happen at any stage of pregnancy, but is more common in the second or third trimester.

Autoimmune diabetes, commonly referred to as type 1 diabetes mellitus (an older synonym is insulin-dependent diabetes mellitus), is a chronic immune-mediated disease characterized by insulin deficiency due to pancreatic islet beta-cell destruction with increasing blood glucose levels.

Medical Scientists at the Helsinki University Hospital (Helsinki, Finland) in a prospective cohort study, analyzed data from 391 women with gestational diabetes and 391 age-, parity- and delivery date-matched controls who delivered from 1984 through 1994 and underwent autoantibody testing during the first trimester of pregnancy. The team assessed levels of four autoantibodies associated with type 1 diabetes: Islet cell autoantibodies (ICA), glutamic acid decarboxylase autoantibodies (GADA), insulin autoantibodies (IAA) and insulinoma-associated antigen-2 autoantibodies (IA-2A). Women completed a follow-up questionnaire assessing later type 1 or type 2 diabetes diagnosis in 2012-2013. The mean follow-up time was 23 years.

The scientists observed single autoantibody positivity in 41(12%) of the gestational diabetes cohort and in eight (2.3%) of the control cohort. In the gestational diabetes cohort, nine (2.6%) tested positive for two autoantibodies and eight (2.3%) tested positive for three autoantibodies, whereas only one woman in the control cohort had two autoantibodies detected. Islet cell autoantibodies (ICA) positivity was found in 12.5% of cases, followed by GADA (6%), IA-2A (4.9%) and IAA (1.2%). In the control cohort, GADA positivity was found in 1.4% of cases, followed by IA-2A (0.8%), IAA (0.6%) and ICA (0.3%). All women with three positive autoantibodies developed type 1 diabetes within seven years from pregnancy with gestational diabetes. Development of type 2 diabetes and gestational diabetes occurred independent of autoantibody positivity.

Kaisu Luiro-Helve, MD, PhD, consultant in obstetrics and gynecology and reproductive endocrinology and senior author of the study, said, “If you are not the typical gestational diabetes candidate, but you have it, that may warrant more screening. Type 1 diabetes is not just a disease of the young. Type 1 usually occurs within 10 years of gestational diabetes, and that is the time when we need to stay alert and perhaps conduct another oral glucose tolerance test. Do not forget about these women after delivery.” The study was presented at the European Congress of Endocrinology virtual meeting held May 22-26, 2021.

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Helsinki University Hospital