Gestational diabetes is a form of diabetes mellitus and is one of the major complications of the perinatal period. It may lead to complications such as fetal developmental malformations, intrauterine distress, fetal death intrauterine neonatal hypoglycemia, giant babies, and difficult or stillbirth. So, what are the causes of gestational diabetes? The following are the causes of gestational diabetes: 1. Genetic basis: Patients who develop gestational diabetes are at high risk of developing type 2 diabetes in the future (but not associated with type 1 diabetes). Therefore, it is thought that the genes causing gestational diabetes and the genes causing type 2 diabetes may be related to each other. 2, obesity: obesity is not only easy to cause type 2 diabetes, but also can cause gestational diabetes. 3, hormone abnormalities: pregnancy placenta will produce a variety of hormones for fetal development and growth, these hormones are very important to the healthy growth of the fetus, but can block the role of insulin in the mother’s body, and therefore cause diabetes. The 24th to 28th week of pregnancy is the peak period of these hormones and is also the time when gestational diabetes often occurs.