There are three different types of diabetes. Type 1 diabetes is usually caused by genetics or diet and requires insulin to treat. Type 2 diabetes, the most common type, is not dependent on insulin to control. It is best controlled by diet and exercise. Gestational diabetes can occur in pregnant women. This will go away after the pregnancy.

It used to be that diabetic women avoided pregnancy and if they did conceive, complications almost always occurred. Today women with diabetes are able to have children. Special attention is paid to their diet and overall healthy but under the care of their doctor they will likely carry their baby to term without much risk.

The above definition applies regardless of whether insulin or only diet modification is used for treatment or whether the condition continues after pregnancy. It is possible that unrecognized glucose intolerance may have antedated or begun concomitantly with pregnancy.

Gestational diabetes (or gestational diabetes mellitus, GDM) is a condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy. Gestational diabetes affects 3-10% of pregnancies, depending on the population studied. No specific cause has been identified, but it is believed that the hormones produced during pregnancy reduce a woman's sensitivity to insulin, resulting in high blood sugar levels.Gestational diabetes generally has few symptoms and it is most commonly diagnosed by screening during pregnancy. Diagnostic tests detect high levels of glucose in blood samples.Babies born to mothers with gestational diabetes are at increased risk of complications, primarily growth abnormalities and chemical imbalances such as low blood sugar. Gestational diabetes is a reversible condition and women who have adequate control of glucose levels can effectively decrease the associated risks and give birth to healthy babies.Women with gestational diabetes are at high risk of developing type 2 diabetes mellitus after pregnancy, while their offspring are prone to developing childhood obesity, with type 2 diabetes later in life. Most patients are treated only with diet modification and moderate exercise but some take anti-diabetic drugs, including insulin therapy.