Pre-existing diabetes and pregnancy

What is diabetes?

Diabetes is a condition where you have too much sugar (glucose) in your blood.

While high blood sugar levels are common to all types of diabetes, this happens for different reasons in different types of diabetes.

In type 1 diabetes, your body can't make insulin. Insulin is a hormone that helps glucose move from your blood into your body's cells. Lack of insulin causes glucose to stay in your blood, causing high blood sugar levels.

In type 2 diabetes, your cells become less sensitive to the insulin made by your body. This means glucose levels build up in your blood. This is known as ‘insulin resistance'.

Gestational diabetes develops during pregnancy, when pregnancy hormones make your body cells more insulin resistant. It usually stops being a problem after your baby is born, but your risk of developing type 2 diabetes after pregnancy stays high.

The information on this page is for people who have diabetes before becoming pregnant.

Pre-pregnancy health check

If you already have type 1 or type 2 diabetes, it's a good idea to visit your doctor and diabetes team 3 to 6 months before you start trying to get pregnant. Managing your blood sugars before getting pregnant and throughout pregnancy gives you the best chance of having a healthy pregnancy and birth.

Your diabetes team can guide you on how to best manage your diabetes and your general health before trying to conceive.

Lifestyle-related things you can do may include:

• blood sugar level monitoring, including appropriate blood sugar level targets
• healthy eating
• avoiding alcohol, smoking and drugs
• keeping a healthy weight
• keeping physically active

Your doctor may also give you advice about medicines, including:

• how much folic acid to take and when to start taking it
• reviewing all your medicines, to make sure they are safe for pregnancy
• making sure all your vaccinations are up to date

Your doctor may also perform some examinations or refer you for tests, to make sure you are well, including:

• health screening tests for medical problems that can occur with diabetes, like high blood pressure, eye problems and foot problems
• blood tests, like routine pre-pregnancy tests and tests related to diabetes

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How does pregnancy affect pre-existing diabetes?

Pregnancy can affect pre-existing diabetes in many different ways. It can make it harder to keep your blood sugar levels steady and within your target range.

During pregnancy, your blood glucose levels tend to be more unstable. If you use insulin, your insulin doses may need to be adjusted more often than usual. If you have type 2 diabetes, you may need to have your medicines adjusted, and/or start to take insulin, even if you haven't had to in the past. Your diabetes team may also adjust your blood glucose targets at different points in the pregnancy.

If you have type 1 diabetes and are taking insulin, your usual hypoglycaemia (‘hypo') warning signs can change in pregnancy, so you may be more likely to suffer from hypos without realising. Your doctor or diabetes nurse may suggest you try continuous glucose monitoring. This means that you use a device that will alert you when your blood sugar level is dropping, without needing to rely on your warning signs. While hypos aren't a risk to your baby, they are important for your own safety and wellbeing.

If you have type 1 diabetes, you may also be at an increased risk of diabetic ketoacidosis (DKA) during pregnancy. DKA happens when you don't have enough insulin for your body to use glucose to make energy. This can be dangerous for you and your baby. DKA can happen to anyone with type 1 diabetes, but you are more likely to develop it if you are unwell or have severe morning sickness. Speak to your diabetes team about making a 'sick day plan', so you know what to do if you get sick when you are pregnant.

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How is diabetes managed during pregnancy?

Your healthcare team

You will be cared for by a team of health professionals which may include:

• an obstetrician who has experience with diabetes or high-risk pregnancies
• a specialist endocrinologist, experienced in diabetes care during pregnancy
• a diabetes educator to help you manage your diabetes
• a dietitian who can give dietary advice at all the different stages — before conception, during pregnancy and after the birth
• a midwife who is experienced in all aspects of pregnancy and birth
• your GP and pharmacist
• a social worker or psychologist

Finding a health professional

Pregnancy, Birth and Baby's service finder helps you locate your nearest doctor, obstetrician, maternal child health nurse, and other health professionals across Australia.

Blood sugar targets

It is very important for your health and your baby's health that you keep your blood sugar levels stable and within the target range.

Your doctor will discuss your individual target range. For most people, the recommended blood sugar levels are between 4.0 and 5.3mmol/L when fasting (before meals), and 5.0 to 6.7mmol/L at 2 hours after a meal.

It's important that your blood sugar levels don't drop significantly below your target ranges (hypo). If you have frequent or severe hypoglycaemic episodes (hypos), your diabetes health team will likely adjust your medicines and/or your blood sugar targets.

Medicines in pregnancy

Some medicines may need to be stopped or changed during pregnancy. Your doctor can guide you on this before you become pregnant, or as soon as possible after you find out you are pregnant.

The doses and types of medicine you need to control your blood sugar levels may change throughout your pregnancy. They might change often. Your doctors will guide you on how often to test your blood sugar levels and what medicines to use.

Some people with type 2 diabetes can control their blood sugars with diet and lifestyle measures before pregnancy or after birth but may find that this needs to change during pregnancy. They may need to start medicines, including insulin, during pregnancy, for optimal blood sugar control.

It's a good idea to check with your doctor before taking any medicine during pregnancy, whether it is prescribed, over-the-counter or herbal. If your doctor isn't available, you can also ask a pharmacist — don't forget to tell them that you have diabetes and that you're pregnant.

Contact your diabetes team for advice if:

• you notice your need for medicines changing significantly – for example, needing much less insulin than before
• your blood sugars becoming more unstable – for example, frequent hypoglycaemic episodes

Possible complications for you or your baby

Diabetes that is not well-controlled during pregnancy can affect your long-term health and can also be risky for your baby.

There is a chance that you may have some of the potential complications of diabetes while you are pregnant, like eye disease and kidney disease. Your doctors can help monitor your risk of having these complications.

High blood sugar levels during pregnancy put you at a higher risk of pregnancy problems including:

• a large baby (over 4.5kg)
• miscarriage or stillbirth
• high blood pressure
• pre-eclampsia
• needing interventions in labour, like a caesarean birth

These risks are reduced if you keep your blood sugars under good control.

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How might pre-existing diabetes affect labour and birth?

Most people with diabetes can have a vaginal birth and will give birth to healthy babies.

If you have diabetes, it's highly recommended you give birth in a hospital, so medical staff are available to help you if there are any problems. It's a good idea to plan in advance where you'd like to birth your baby and who you'd like to be with you.

If your blood sugar levels have been high during your pregnancy, or your baby is expected to be large (over 4.5kg), your doctor may recommend certain interventions. These may include induction of labour before or on your expected due date, or a caesarean birth. Your doctor will give you advice based on your specific circumstances.

During labour and birth, your blood sugar levels will be monitored closely by your medical team. You might have an intravenous (IV) drip with sugar and insulin while in labour, or the doses of your insulin will be adjusted by your medical team around your labour or caesarean section.

After birth, your baby will be monitored closely and have a heel-prick blood test every few hours for the first 1 to 2 days to check for low blood sugar levels. If your baby has low blood sugar, they may need extra feeds with expressed colostrum, expressed breastmilk, infant formula or glucose. If they continue to have low blood sugar level, they may also need an intravenous (IV) glucose drip and/or monitoring in the hospital's special care nursery.

How might pre-existing diabetes affect breastfeeding?

Having diabetes won't usually affect your ability to breastfeed, and breastfeeding can be helpful to your health and your baby's health. Not all diabetes medicines can be safely used during breastfeeding, so check with your doctor whether you can continue to use the medicines you used while you were pregnant. Insulin is usually safe to use while breastfeeding.

Your doctor or midwife may recommend expressing colostrum in the late stages of your pregnancy. Any colostrum you express can be used for supplemental feeds to treat low blood sugar, if your baby needs them.

You can talk to your doctor, midwife or lactation consultant about any concerns about breastfeeding with diabetes. You can also call the Australian Breastfeeding Association on 1800 686 268 for breastfeeding support.

Resources and support

Diabetes Australia have detailed e-books about pregnancy with both type 1 and type 2 diabetes, as well as helpful information about planning for pregnancy with diabetes.

If you are pregnant or breastfeeding and would like to find out more about your medicines call Medicines Line on 1300 633 424.

Videos about diabetes in pregnancy are available from Diabetes Australia in different languages.

More information is also available from the Pregnancy and Diabetes website of the National Diabetes Services Scheme.

You can contact the NDSS Helpline on 1800 637 700 for information and support.