What is gestational diabetes?

If you don’t produce enough insulin to control your blood sugar levels during pregnancy, you may develop gestational diabetes mellitus (GDM).

GDM happens during pregnancy and usually goes away after birth. It usually occurs in the second half of pregnancy, but it can happen at any time. However, having GDM puts you at increased risk of developing diabetes in later life.

There is more chance of developing GDM if you have any of the following risk factors:

  • had gestational diabetes before
  • a body mass index above 30 (obese)
  • had a baby who weighed 4.5kg (10lbs) or more at birth
  • parents or siblings with diabetes
  • family origins from South Asia, China, Africa, Caribbean or the Middle East

Most women do not have any symptoms of GDM; therefore it is very important to be tested if you have any of the above risk factors

The test for GDM is done usually between 24-28 weeks of pregnancy but is earlier if you have had previous GDM or any of the other risk factors listed above.

The risks of gestational diabetes to your pregnancy

It is very important that your blood sugars are well controlled in pregnancy as this reduces the risks associated with GDM such as:

  • your baby growing larger than usual, causing problems during labour and birth
  • too much fluid around the baby (known as polyhydramnios)
  • preterm birth (birth before 37 weeks of pregnancy)
  • pre-eclampsia, which causes high blood pressure that if untreated can put the pregnancy at serious risk
  • your baby developing low blood sugar after birth, which may need treatment
  • a slight increased risk of stillbirth

Diagnosing and managing GDM

Early in your pregnancy, you will be offered a test for GDM by your Midwife or GP if you have any of the above risk factors. If you are diagnosed with GDM, you will be looked after by a specialist maternity team within the hospital, who will help you to manage your blood sugars.

After pregnancy

After the pregnancy, your blood sugars should return to normal. However, your blood sugars will be checked within 6 to 13 weeks after delivery and yearly thereafter. These yearly checks are very important as you are at increased risk of type 2 Diabetes; but most importantly, a healthy diet and healthy weight can reduce these risks. 

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