Raised blood sugar can damage blood vessels leading to kidney damage and eye damage, vascualr remodelling leads to raised blood pressure and heart disease.
Babies of GDM mothers may have more birth weight, preterm birth and respiratory distress, low blood sugar shortly after birth and hypoglycemic seizures, still birth and obesity/ diabetes later in their life.
Exact cause is unknown but most appreciated hypothesis is either low insulin or insulin resistance due to genetic +/- environmental factors. Symptoms and signs include increased thirst, extreme hunger, unexplained weight loss, frequent urination, fatigue, irritability, blurred vision, slow healing wounds, presence of ketones in urine, fruity odour and frequent infections.Treatment is either tablets or insulin to control blood sugar levels along with life style modifications (Diet + exercise).
Yes, one only needs to study and pass to get a degree to be a doctor irrespective of their own medical conditions.
With time, raised blood sugar can damage back of the eye - retina causing Diabetic retinopathy, which left untreated can lead to blindness.