Diabetes and pregnancy

One in twenty pregnant women in Australia is affected by diabetes. Although the disease can cause serious complications for mothers and babies, good planning and comprehensive antenatal care can keep you and your baby healthy. By Joanna Egan.

pdfAlso available in Health Journey 2013 Issue 2

pregnant woman having blood test
Diabetes is a chronic condition characterised by the body's inability to control glucose levels in the blood. Glucose is a simple sugar found in foods such as breads, cereals, fruit, starchy vegetables, legumes, dairy products and sweets. A hormone produced by the pancreas, called insulin, converts this glucose into energy that is used to fuel the body. When a person has diabetes, they either don't produce enough insulin or are unable to use insulin effectively. This causes glucose to build up in their bloodstream. There are several types of diabetes:

Type 1: People with type 1 diabetes don't produce insulin. As a result, they need to monitor their blood glucose levels carefully and require regular insulin injections (up to four times a day). Generally, type 1 diabetes arises in children and young adults, but it can occur at any age.

Type 2: This is the most common form of diabetes. Some people have a genetic predisposition to developing the disease but often, it is caused by lifestyle factors such as high blood pressure, obesity, insufficient exercise and poor diet. People with type 2 diabetes produce insulin, but either don't produce enough or are unable to use it effectively. Generally, it is initially managed with healthy eating and regular physical activity, but as the condition progresses, glucose-lowering tablets and/or insulin injections may be prescribed.

Gestational diabetes: This form of diabetes develops, or is first diagnosed, during pregnancy. It usually appears late in the second trimester and resolves after childbirth. Most women are screened for it between 26 and 28 weeks of pregnancy. Women with gestational diabetes are either unable to produce enough insulin or unable to use insulin effectively.

Managing the condition involves regular exercise and healthy eating. Some women also require medication, such as insulin injections. Women with gestational diabetes have an increased risk of developing type 2 diabetes and/or cardiovascular disease later in life – 17 per cent of women with gestational diabetes develop type 2 diabetes within 10 years and 50 per cent develop it within 30 years.

How will diabetes affect me during pregnancy?

During pregnancy, the body's energy needs, and therefore our insulin requirements, increase. Many women find it challenging to manage healthy blood glucose levels as the physical and hormonal changes that occur during pregnancy take place. All forms of diabetes can cause serious complications for you and your baby during pregnancy, labour and delivery. Women with pre-existing diabetes (type 1 or 2) are at higher risk than those with gestational diabetes.

Early pregnancy: Women with pre-existing diabetes have a higher risk of miscarrying. Those with type 2 often need to adjust their medication early in pregnancy; many switch from tablets to insulin injections. Women with type 1 diabetes are risk having severe 'hypos' (episodes of low blood glucose). Often, the usual warning signs, such as feeling sweaty or shaking, change or disappear during pregnancy. To avoid unexpected hypos, you should be careful not to skip meals. You should also always carry foods to quickly treat hypos, such as jelly beans, carbohydrate snacks and glucose tablets.

Mid-pregnancy: During pregnancy, hormones produced by the placenta interfere with the normal function of insulin. Rather than converting glucose from food into energy for your body's cells, the energy is directed to your baby. As a result, your insulin needs begin to rise rapidly from about week 20. By the time you reach 30 weeks, you may need to take two-to-three times your pre-pregnancy insulin dose.

Late pregnancy: Mothers with pre-existing or gestational diabetes are more likely to have a pre-term (prior to 37 weeks), or very pre-term (before 32 weeks) birth. On average, one-in-five women with type 1 or 2 diabetes and almost one-in-ten mothers with gestational diabetes give birth at 32-36 weeks. Women with diabetes are more likely to have an induced labour, an instrumental birth (delivery with forceps or ventouse) or a caesarean section. Women are also at greater risk of developing hypertension (high blood pressure) and pre-eclampsia (a dangerous condition characterised by high blood pressure and water retention).

Post-birth: Some of the long-term complications of diabetes – kidney disease, eye disease and cardiovascular disease – can either appear for the first time or worsen during pregnancy. In many cases, eye and kidney deterioration resolves after childbirth, but for some women, the damage can be long-lasting or irreversible.

Can diabetes affect my baby?

Throughout pregnancy, labour and delivery, serious complications can occur. They can affect the short- and long-term health of your baby.

Early pregnancy: Babies of mothers with pre-existing diabetes are at an increased risk of suffering heart, spine and kidney damage if the mother has high blood glucose levels. Miscarriage can also occur. To reduce your baby's risk, you should monitor your blood glucose carefully and try to maintain healthy levels.

Throughout pregnancy: When you experience high blood sugar levels, excess glucose passes through the placenta to your foetus. As a result, your baby produces high levels of insulin to convert this extra glucose into energy. This can cause your baby to grow faster and larger than it needs to. After birth, large babies may have low glucose levels for a day or two because they continue to produce high levels of insulin. They may also have trouble breathing and feeding. When you experience low blood glucose levels during pregnancy, your baby is not affected in the same way that you are; your baby is able to maintain its own blood glucose, even when your levels drop.

Late pregnancy: The most serious complication for your baby in the late stages of pregnancy is foetal death. Babies born to mothers with pre-existing diabetes are more likely to be stillborn than those born to mothers with gestational diabetes, but all are at risk. In general, babies are also more likely to be born pre-term and as a result, they often require high-level resuscitation at birth. Many need to be admitted to special care nurseries or neonatal intensive care units.

Post-birth: The effects of heart, spine and kidney damage, which can occur during early pregnancy, can affect infants throughout their lives. Babies born to mothers with diabetes are also more likely to become obese and to develop type 2 diabetes in early adulthood.

How can I protect myself and my baby?

Women with diabetes can have healthy pregnancies and babies. It is important to try to establish healthy blood glucose levels before pregnancy. If you have an unplanned pregnancy, stabilising your blood glucose as soon as you find out you're pregnant is critical because your baby's major organs develop during the first eight weeks. Paying careful attention to nutrition and maintaining general fitness can help you control your blood glucose levels.

Before you conceive, or as soon as possible afterwards, your doctor will want to test you for diabetes-related complications. You may undergo a physical exam to check for nerve damage; you will be asked to provide a urine sample so your kidney function can be assessed and your doctor will recommend that you visit an ophthalmologist to have your eyes assessed.

During pregnancy, your diabetes medication will need to be carefully monitored. If you have type 2 diabetes and are taking tablets prior to pregnancy, your doctor may advise that you convert to insulin in order to better control your glucose levels. During labour and delivery, your endocrinologist will keep an eye on your levels. They will adjust your insulin dosage directly after your baby is born to safeguard you against hypoglycaemia.

If your baby is producing high levels of insulin during your pregnancy in response to your high glucose levels, their blood sugars could be low following birth. If left untreated, this could lead to seizures. Your baby's blood glucose levels will be tested (by heel prick) every four hours for the first 24 hours of their life. If their glucose levels are very low, they may need to have supplementary feeds. Insulin does not pass into your breastmilk, so it is safe for mothers to breastfeed their babies. Breastfeeding within 30 to 60 minutes of birth can reduce the risk of your baby having low blood sugar. Regular feeds (every three to four hours) can help them to maintain blood glucose levels.

Mothers with gestational diabetes are at risk of developing type 2 diabetes later in life. You will typically be offered an oral glucose tolerance test about 6-8 weeks after giving birth. This test assesses whether your blood glucose levels are within the normal range. The test should be repeated every three years.

Where can I go for help?

Diabetes Australia offers phone support and information sessions, and hosts face-to-face support groups for women. The Australasian Diabetes in Pregnancy Society provides up-to-date, evidence-based resources.

Last updated: June 2013

© Women’s Health Queensland Wide Inc. This article was written by Joanna Egan and reviewed by the Women’s Health Queensland Wide editorial committee. It was published in Health Journey 2013 Issue 2.

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