Gestational diabetes mellitus (GDM) is high blood sugar first detected during pregnancy. It is common, often has no symptoms, and is usually manageable when found on time.
Why it happens
Placental hormones reduce the body's sensitivity to insulin. In most pregnancies the pancreas compensates, but sometimes blood sugar still rises. This is not a sign of "doing something wrong"; GDM can happen to anyone.
Why it matters if untreated
- Larger baby and birth complications
- Higher risk of pre-eclampsia
- Low blood sugar in the baby after birth
- Higher future risk of type 2 diabetes for the mother
When GDM is detected and managed on time, these risks can be greatly reduced.
What the test is like
The usual WHO diagnostic window is 24-28 weeks. The test is often an oral glucose tolerance test: blood sugar is checked fasting, then again after a sweet drink. It takes about two hours, so bring water and something to read.
If GDM is diagnosed
Most cases can be managed with nutrition changes and moderate activity. Some people need home glucose monitoring, and fewer need insulin. Blood sugar often returns to normal after birth, but your healthcare provider will recommend follow-up testing.
Your healthcare provider decides whether and how you should be tested. Some women are tested earlier.