Gestational Diabetes Mellitus Future risk for mother and child

Gestational diabetes mellitus (GDM) occurs as a complication in 2% of all pregnancies in Sweden. Women with GDM have a substantial risk of developing type 2 diabetes later in life, but the risk of developing type 1 diabetes is also increased. GDM increases the risk for macrosomia and caesarean delivery. However, long term prognosis and eventual future risks for children born to mothers with a previous GDM are less well studied. In this thesis women who had GDM during 1995-2010 and their children were investigated. Aims Paper I-III: Determine how many women with GDM that have beta-cell specific autoantibodies such as glutamic acid decarboxylase antibodies (GADA), tyrosine phosphatase antibodies (IA-2A) and zink transporter 8 antibodies (ZnT8A) during pregnancy, and follow these women after delivery to estimate the risk for later development of type 1 diabetes. Evaluate C-peptide levels in women with GDM as a predictor for future development of diabetes. Aims Paper IV: Investigate the effects of maternal GDM on childhood body mass index (BMI) compared to the age-specific reference values in Sweden and to their siblings born after a non-GDM pregnancy. Results Paper I-III: Up to 8% of women with GDM had GADA or IA-2A during pregnancy, and 50% of these women developed type 1 diabetes later in life. GADA was the most frequent autoantibody. When adding ZnT8A as an autoimmune marker in GDM, the number of autoantibody positive women increased by 2%. C-peptide analyses did not add any valuable information for development of either type 1 or type 2 diabetes. Results Paper IV: BMI for boys was higher at ages 7-10 and for girls at birth and ages 4-12 compared to Swedish reference values. The same BMI pattern was found in siblings born after a non-GDM pregnancy. Conclusions Paper I-III: Since 50% of women with autoantibodies during GDM develop type 1 diabetes later in life, at least GADA analyses should be performed in all women with GDM by routine. Conclusions Paper IV: Children to women with a prior GDM have a high risk for overweight and obesity. This is thought to be due to life style habits in the family rather than prenatal factors, even if genetic factors could not be tested in this study, since similar BMI pattern was found in siblings. Early life style intervention is therefore very important in these families.