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HealthInfo Canterbury

Diabetes in pregnancy

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If you already have diabetes or you develop gestational diabetes in pregnancy you need to be referred to the specialist diabetes team at Christchurch Women's Hospital. You can continue to receive care from your lead maternity carer (midwife or GP) in the community as well.

Gestational diabetes

FDP pregnant womanAround 3.7% of pregnant women develop gestational diabetes mellitus, also called gestational diabetes. This happens because hormones made by the placenta during late pregnancy make it harder to control blood sugar levels. Some women can't make enough insulin to keep up with these changes, and their glucose levels rise.

When the mother's glucose level rises, so does the baby's, which can make it produce too much insulin. This can make the baby grow too much, and also has some other harmful effects.

Some women have a higher risk of developing gestational diabetes. This includes women who:

All pregnant women are offered an antenatal blood test early in their pregnancy. This includes the HbA1c test, which screens for diabetes.

Later in pregnancy, at around 27 to 28 weeks, your lead maternity carer should screen you for gestational diabetes. This is done using a blood test called the polycose test. For this test, you will be given a drink containing glucose (sugar). A sample of your blood will be taken one hour later. If the test is high, you will need to have a second test, called the glucose tolerance test.

If your lead maternity carer suspects you are developing diabetes after 28 weeks, they may also screen you again later in your pregnancy.

Diabetes New Zealand has more information on Gestational diabetes.

Type 1 diabetes

If you have type 1 diabetes you will be taking insulin to control the sugar levels in your blood. It is important to have good control of your sugar levels before becoming pregnant to avoid unnecessary complications. Insulin is safe in pregnancy and should not be stopped.

Ideally you should make an appointment with either your GP or diabetes specialist in the months before you plan to become pregnant. You should also take a higher dose of folic acid than women without diabetes (5 mg daily). You will need a prescription from your doctor for this.

Type 2 diabetes

If you have type 2 diabetes you may be taking medication to control your sugar levels. It is important to plan for pregnancy and to have good sugar control before becoming pregnant. Ideally you should make an appointment with your GP or diabetes specialist in the months before you become pregnant so that any medication adjustments can be made. If you become pregnant unexpectedly, do not stop your medication, but make an appointment to see your GP as soon as possible.

It is important to try to maintain a healthy weight both before and during your pregnancy. You should also take a higher dose of folic acid than women without diabetes (5 mg daily). You will need a prescription from your doctor for this.

  HealthInfo recommends the following pages

Written by HealthInfo clinical advisers. Endorsed by Diabetes Centre, Christchurch Hospital. Updated May 2016.

Sources

See also:

Understanding your HbA1c results

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