Treatment of diabetes in pregnancy

Date: September 2017, Version 1

What is diabetes?

Diabetes is a condition in which the blood sugar levels are too high. This can have serious effects on the body, both in the short- and long-term.

In type 1 diabetes, the body no longer produces the hormone insulin which regulates blood sugar levels. Treatment of type 1 diabetes is with injected insulin.

In type 2 diabetes, insulin is still produced but the body doesn’t respond to insulin appropriately. Type 2 diabetes is often linked to obesity and is initially treated with diet and exercise. If this is ineffective, oral medicines that lower the blood sugar (such as metformin) and/or injected insulin may be used.

Gestational diabetes occurs during pregnancy and usually gets better on its own after the baby is born. Treatment of gestational diabetes is the same as for type 2 diabetes.

How can diabetes affect pregnancy?

It is important that women with diabetes diagnosed prior to pregnancy (pre-existing diabetes) maintain good control of their blood sugar levels while attempting to conceive and once pregnant.

Pre-existing diabetes has been linked to an increased chance of birth defects in the baby and the best way to minimise this risk is to maintain good blood sugar control in the first trimester. Gestational diabetes is not thought to increase the chance of birth defects in the baby.

Good blood sugar control throughout pregnancy is also critical to reduce the chance of other adverse pregnancy outcomes. All types of diabetes in pregnancy can increase the chance of the baby being larger than expected, leading to possible complications during delivery and the baby having hypoglycaemia (low blood sugar) after birth, which may require short-term treatment. Diabetes in pregnancy is also thought to increase the chance of miscarriage, stillbirth, premature birth, and death of the baby after delivery. These risks are highest if blood sugar control is poor.

Which diabetes treatments are recommended during pregnancy?

It is essential that women with type 1 diabetes continue insulin treatment during pregnancy. Insulin does not cross the placenta and is safe in pregnancy.

Women with type 2 diabetes who are planning to conceive may be advised to attempt to control their condition with diet and exercise. If oral medication is required to control type 2 diabetes, either while attempting conception or during pregnancy, metformin is advised as the first choice. Women taking oral diabetes medicines other than metformin may therefore be advised to switch. If insulin is required, this is considered safe for use in pregnancy.

Women with gestational diabetes will likely be advised to first try and control the condition with diet and exercise before metformin or insulin are offered.

Ideally, women with diabetes should discuss their medication requirements with their doctor prior to conception. Diabetic women with an unplanned pregnancy should contact their doctor as soon as possible.

Can use of diabetes treatments in pregnancy harm my baby?

A baby’s body and most internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that some medicines are known to cause birth defects. There is no proof that treatment with insulin or metformin during pregnancy causes birth defects in the baby, or any other adverse pregnancy outcomes. In fact, because the adverse pregnancy outcomes that are linked to diabetes have a higher chance of occurring where blood sugar control is poor, use of these medicines has been shown to reduce the risk of some adverse pregnancy outcomes.

Will I or my baby need extra monitoring during pregnancy?

As part of their routine antenatal care, most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects and to check the baby’s growth.

Women with diabetes will receive additional monitoring during pregnancy, including blood tests to measure blood sugar control, eye checks, and extra scans to assess the growth of the baby and amniotic fluid levels.

Are there any risks to my baby if the father has diabetes?

We would not expect any increased risk to your baby if the father has diabetes and/or used a diabetes treatment before or around the time you became pregnant.

Who can I talk to if I have questions?

If you have any questions regarding the information in this leaflet please discuss them with your healthcare provider. They can access more detailed medical and scientific information from

How can I help to improve drug safety information for pregnant women in the future?

Our online reporting system (MyBump Portal) allows women who are currently pregnant to create a secure record of their pregnancy, collected through a series of questionnaires. You will be asked to enter information about your health, whether or not you take any medicines, your pregnancy outcome and your child's development. You can update your details at any time during pregnancy or afterwards. This information will help us better understand how medicines affect the health of pregnant women and their babies. Please visit the MyBump Portal to register.

General information
Sadly, miscarriage and birth defects can occur in any pregnancy.

Miscarriage occurs in about 1 in every 5 pregnancies, and 1 in every 40 babies are born with a birth defect. This is called the ‘background risk’ and happens whether medication is taken or not.

Most medicines cross the placenta and reach the baby. For many medications this is not a problem. However, some medicines can affect a baby’s growth and development.

If you take regular medication and are planning to conceive, you should discuss whether your medicine is safe to continue with your doctor/health care team before becoming pregnant. If you have an unplanned pregnancy while taking a medicine, you should tell your doctor as soon as possible.

If a new medicine is suggested for you during pregnancy, please make sure that the person prescribing it knows that you are pregnant. If you have any concerns about a medicine, you can check with your doctor, midwife or pharmacist.

Our Bumps information leaflets provide information about the effects of medicines in pregnancy so that you can decide, together with your healthcare provider, what is best for you and your baby.