Find out more about your stage of pregnancy

Gestational diabetes

Diabetes is a condition in which there is an inability to control blood sugar levels and it leads to high amounts of sugar in the blood. Gestational diabetes is diabetes that develops during pregnancy. It happens because your body cannot produce enough insulin (a hormone important in controlling blood glucose) to meet its extra needs in pregnancy and/or because your body is more resistant than usual to insulin. The result is that blood sugar levels go up.

Any woman can develop gestational diabetes though some women are at more risk than others (see below). Diabetes affects around three to five in every 100 pregnant women (3-5%).

Most women who develop diabetes in pregnancy have healthy pregnancies and healthy babies but occasionally gestational diabetes can cause serious problems, especially if it goes unrecognised. It is associated with stillbirth and premature labour and needs careful monitoring to reduce these risks.

Gestational diabetes starts during pregnancy and stops after the baby is born.

What are the risks of gestational diabetes?

Any form of diabetes - including diabetes that developed before the pregnancy - must be managed carefully because it is associated with complications such as:

  • premature birth
  • giving birth to a large baby
  • having problems during the birth, such as shoulder dystocia (where the shoulder gets stuck after delivery of the head)
  • the death of the baby around the time of the birth.

Your baby may also be at risk of becoming obese and/or developing diabetes later in life.

Controlling your levels of blood glucose during pregnancy and labour reduces the risks of all these complications for you and your baby (see below).

Am I at risk of gestational diabetes?

You are at higher risk of developing gestational diabetes if you:

  • have a BMI (body mass index) of 30 or higher
  • had a previous large baby (weighing 4.5 kg/10lbs or above)
  • had gestational diabetes before
  • have a parent, brother or sister with diabetes
  • your family origin is South Asian, Chinese, African-Caribbean or Middle East.

Treating gestational dabetes

If they think you might have diabetes, the healthcare team will ask questions and you may have a simple blood test in early pregnancy and/or a glucose tolerance test (GTT) when you are between 24 and 28 weeks pregnant. If you test positive, you and your baby will be carefully monitored throughout your pregnancy, and you will be shown how to monitor your own glucose levels. If you have had gestational diabetes in a previous pregnancy you will also be offered this test or a testing kit.

Diet and exercise

Changing your diet and exercising regularly are the most important things you can do to improve gestational diabetes. Your healthcare team should give you information on eating healthily and exercising.

Most women who make these changes see an improvement but the small number who don’t are given tablets or insulin injections. If insulin injections are recommended you will be shown how to inject yourself.

Read more about having a healthy diet in pregnancy here.

Read more about exercising in pregnancy here.

We value your feedback! Every month we will choose one person at random who feeds back to WIN a high street voucher!
Questions that require an answer are marked with  *
* Was this page helpful?
* Please tell us more...
* Email address

The causes and problems of premature birth

Your premature baby:

You can also read about

Reviewed June 2014, next review June 2017


RCOG (2013) Information for you Gestational diabetes, Royal College of Obstetricians and Gynacologists

J David, Steer P et al (2010) High risk pregnancy, management options, Elsevier Saunders

NICE (2008) Diabetes in pregnancy Management of diabetes and its complications from pre-conception to the postnatal period, clinical guideline 63, National Institute for Health and Clinical Excellence


Copyright © Tommy's. TOMMY'S is registered charity no 1060508 and SCO39280