Gestational diabetes is a transient form of diabetes that occurs during pregnancy. It's caused by an alteration in hormones during pregnancy. Gestational diabetes affects about 4% of pregnant women. The incidence is higher in women of Southern Asian, Aboriginal or Torres Strait Islander background. 

This form of diabetes usually develops around the second trimester of pregnancy and disappears after delivery. Uncontrolled gestational diabetes can result in complications for the pregnant woman and the baby. Treatment includes an appropriate diet, exercise and in some cases medication.