Diabetes is the most common medical complication in pregnancy. Women with diabetes in pregnancy can be divided into two groups such as pregestational diabetes which complicates less than 1% of all pregnancies is defined as type 1 (previously referred to as insulin-dependent diabetes mellitus or juvenile-onset diabetes mellitus) or type 2 diabetes (previously referred to as non-insulin-dependent diabetes mellitus or adult-onset diabetes mellitus) that exists before the pregnancy. In about 2% of all pregnancies, the glucose intolerance is first diagnosed during pregnancy and is termed gestational diabetes. Gestational diabetes is further subdivided according to the degree of severity of the glycemic control disturbance. The risk of major congenital malformations is significantly higher in women with pregestational diabetes mellitus, especially when glycemia is not well controlled during the periconceptional period. This chapter covers the caudal regression syndrome, structural cardiac defects and cardiac anomalies, Donald school textbook of diabetic pregnancy and ultrasound central nervous system anomalies and neural tube defects, gastrointestinal anomalies, and femoral hypoplasia-unusual facies syndrome.