It is common for blood sugar to rise during pregnancy because of hormonal changes. But if your high blood sugar persists, you could develop gestational diabetes mellitus (GDM).

What is gestational diabetes?

The excess blood sugar in the body can harm both the mother and the baby. Gestational diabetes occurs because the body does not produce enough insulin, a hormone which controls blood sugar level. During pregnancy, the placenta produces a number of hormones, some of which may impair the production and function of insulin.

“Usually, gestational diabetes develops after the 20th week of pregnancy,” says the Department of Obstetrics and Gynaecology, KK Women’s and Children’s Hospital (KKH), a member of the SingHealth group. “In most cases, it disappears after the delivery of the baby.”

Risk factors for gestational diabetes

It is not clear why some pregnant women develop gestational diabetes and others don’t. Your risk for developing gestational diabetes increases if you:

  • Are over the age of 25 when you become pregnant

  • Are overweight before you become pregnant

  • Have pre-diabetes before you become pregnant

  • Have a family history of diabetes

  • Have high blood pressure

  • Had a previous pregnancy in which you:

    • Had an unexplained miscarriage or stillbirth

    • Gave birth to a baby who weighed over 4 kg

Symptoms of gestational diabetes

Typically, women with gestational diabetes display no symptoms. Their raised blood sugar level is likely to be discovered during a routine prenatal checkup. However, in some cases, the following symptoms may be present:

  • Increased thirst

  • Increased urination

  • Increased appetite

  • Increased fatigue

Diagnosis of gestational diabetes

Pregnant women who are at high risk for gestational diabetes are likely to be given an oral glucose tolerance test early in their pregnancy, possibly during the first prenatal visit, to screen for diabetes. For other women, the test is usually given between weeks 24 to 28 in their pregnancy.

Ref: R14