Gestational diabetes and premature birth

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.

Premature baby in incubator.

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 diabetes

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 gestational diabetes here



  1. RCOG (2013) Information for you Gestational diabetes, Royal College of Obstetricians and Gynacologists
  2. J David, Steer P et al (2010) High risk pregnancy, management options, Elsevier Saunders
  3. 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
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Explaining premature birth

  • Profile of pregnant woman drawn in chalk on black board.

    Intrauterine infection

    Intrauterine infection is infection within the womb. Research suggests that intrauterine infection may be responsible for as many as 40 percent of preterm births, and is also a risk factor for stillbirth.

  • Premature baby in incubator.

    Gestational age and medical needs

    As soon as your baby is born, the healthcare team will decide what level of care he needs. His health will often depend on how prematurely he was born. The chart below gives a very rough guide to how different ages of gestation could affect your baby.

  • Pregnant woman being checked by midwife.

    Problems with your baby's growth in the womb

    Intrauterine growth restriction (IUGR), also known as fetal growth restriction (FGR) is a condition in which a baby's growth slows or stops when they are in the womb.

  • Premature baby.

    Lifestyle and premature birth

    The way your life is lived can have an effect on your risk of premature birth. There are some things that you will not be able to change, such as ethnicity or age but there are some others that you may be able to change.

  • Couple at antenatal appointment.

    Your pregnancy history

    Your history of previous pregnancies and your medical history are factors in determining your risk of premature delivery.

  • Pregnant woman talking to health professional.

    Antiphospholipid syndrome

    Antiphospholipid syndrome (APS) is an autoimmune disorder in which the body’s immune system makes antibodies that attack and damage its own tissues or cells.

Last reviewed on June 1st, 2014. Next review date June 1st, 2017.

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