Gestational diabetes mellitus (GDM) is a form of diabetes that occurs during pregnancy. It develops when hormones produced by the placenta interfere with the body’s ability to use insulin effectively, leading to elevated blood sugar levels.

The exact cause isn’t fully understood, but experts suggest that hormonal changes during pregnancy may disrupt insulin’s ability to regulate blood sugar. As the placenta grows, it produces more of these hormones, which can heighten the risk of insulin resistance.

Gestational diabetes can develop in any pregnant woman, but certain factors may increase the risk, including:
• Being over 25 years old
• Being overweight or obese
• Family history of diabetes
• Impaired glucose tolerance
• Previous gestational diabetes
• Have given birth to a baby weighing more than 4.5kg (10lbs)
• Of certain ethnic backgrounds (e.g., Asian, Black, African-Caribbean, or Middle Eastern origin)

Gestational diabetes often doesn’t cause noticeable symptoms and can be easily mistaken for common pregnancy signs, such as increased thirst, frequent urination, or fatigue. Most cases are detected through routine blood sugar screening during pregnancy.

Gestational diabetes is usually screened between 24 and 28 weeks of pregnancy. The process typically involves fasting overnight, followed by a fasting blood test to measure your baseline glucose level. Afterward, you’ll be given a glucose drink, and a second blood sample will be taken to assess how your body processes the glucose.

Unmanaged gestational diabetes can lead to complications. Potential risks for the baby include:
• Excessive birth weight (macrosomia)
• Low blood sugar after birth (hypoglycaemia)
• Premature delivery
• A higher likelihood of developing type 2 diabetes later in life

In most cases, gestational diabetes resolves after childbirth. However, women who have experienced gestational diabetes have an increased risk of developing type 2 diabetes later in life. Follow-up screenings for diabetes are typically offered 6 to 13 weeks postpartum, with ongoing screenings recommended for long-term monitoring.

The risks associated with gestational diabetes are typically manageable and, in some cases, preventable. Effective management includes:
• Regularly monitoring blood sugar levels
• Maintaining a balanced diet with controlled carbohydrate and sugar intake
• Engage in regular physical activity
• Using insulin or other medications when necessary

To learn more about gestational diabetes, consult your doctor or midwife for personalized advice and resources. You can also visit your country’s health organisation website for reliable information and access trusted information. You may also find helpful guides and insights on our resources page.