Sex of the baby and future maternal risk of Type 2 diabetes in women who had gestational diabetes

Aims Women who develop gestational diabetes mellitus have a chronic defect in the secretion of insulin by the pancreatic β cells that underlies both their diagnostic hyperglycaemia in pregnancy and their elevated lifetime risk of developing Type 2 diabetes in the future. It has recently emerged that carrying a male fetus is associated with poorer maternal β‐cell function and an increased risk of gestational diabetes, whereas the development of gestational diabetes when carrying a girl (as compared with a boy) predicts a comparatively higher risk of early progression to Type 2 diabetes before any subsequent pregnancy. In this context, we sought to determine the impact of fetal sex on the long‐term risk of Type 2 diabetes in women with gestational diabetes. Methods Using population‐based administrative databases, we identified all women in Ontario, Canada, with a singleton live‐birth first pregnancy complicated by gestational diabetes between April 2000 and March 2010 ( n = 23 363). We compared the risk of subsequent Type 2 diabetes after pregnancy in those who carried a girl ( n = 11 229) vs. those who carried a boy ( n = 12 134). Results Over median 5.5 years follow‐up, 5483 women (23.5%) were diagnosed with diabetes. Compared with those who carried a boy, women who had a girl had an elevated risk of subsequently developing diabetes (adjusted hazard ratio = 1.06, 95% CI 1.01–1.12). Conclusions Among women with gestational diabetes, those who are carrying a girl have a slightly higher overall future risk of Type 2 diabetes.