Gestational diabetes is diabetes diagnosed for the first time during pregnancy (gestation). Like other types of diabetes, gestational diabetes affects how your cells use sugar (glucose). Gestational diabetes causes high blood sugar that can affect your pregnancy and your baby's health.

Gestational diabetes (GD or GDM) is a type of diabetes that develops exclusively in pregnancy when blood sugar levels get too high (hyperglycemia). It happens when the hormones from the placenta block your ability to use or make insulin. Insulin helps your body maintain the right amount of glucose in your blood.

Gestational diabetes happens when your body can't make enough insulin during your pregnancy. Insulin is a hormone made by your pancreas. It acts like a key to let blood sugar into the cells in your body for use as energy.