Diabetes in pregnancy

Published by Bupa's Health Information Team, March 2010.

This factsheet is for women who have diabetes that develops in pregnancy (gestational diabetes), or who would like information about it. It doesn't give advice for women who already have diabetes and would like to become pregnant.

Diabetes can develop during pregnancy in women who haven't previously had the condition. This is called gestational diabetes, and it affects around two to seven out of 100 pregnant women. It can lead to problems for the mother and baby if it isn't properly controlled.

About diabetes in pregnancy

Diabetes is a condition in which your blood sugar (glucose) level is high because there isn't enough insulin in your blood, or your body isn't responding to insulin properly. Insulin is a hormone that allows your body to break down sugar in your blood to be used as energy.

During pregnancy, various hormones block the usual action of insulin. This helps to make sure your growing baby gets enough sugar. Your body needs to produce more insulin to cope with these changes. Gestational diabetes develops when your body can't meet the extra insulin demands of the pregnancy.

Gestational diabetes usually begins in the second half of pregnancy, and goes away after your baby is born. If gestational diabetes doesn't go away after your baby is born, it's possible that you already had a slowly developing form of what is known as type 1 diabetes, and that it was picked up by chance during your pregnancy. The other form of diabetes is called type 2 diabetes and both type 1 and 2 are lifelong conditions.

Symptoms of diabetes in pregnancy

Gestational diabetes doesn't usually cause any symptoms. Sometimes you may have symptoms of high blood sugar, including:

• increased thirst
• needing to urinate often
• feeling tired

However, these are also common symptoms of a normal pregnancy.

Complications of diabetes in pregnancy

Gestational diabetes isn't an immediate threat to your health. However, poorly controlled diabetes in pregnancy puts you at a higher risk of various problems. These include:

• a condition called pre-eclampsia, which causes high blood pressure
• premature labour
• having too much amniotic fluid (the fluid around your unborn baby)

If you have gestational diabetes, you're more likely to need a caesarean delivery than women who don't have diabetes.

You're also more likely to develop gestational diabetes in future pregnancies, and are at a higher risk of developing type 2 diabetes later in life.

For your baby

If you have high blood sugar levels, your baby may grow to be larger than usual. This is because he or she has to make extra insulin to control the increased blood sugar, which causes more fat and tissue to be stored. This can make delivery difficult. For example, there is an increased risk of shoulder dystocia. This is when your baby's head has been born but one of his or her shoulders is stuck behind your pelvic bone, preventing his or her body being delivered. This in turn can damage nerves in your baby's neck or result in a fracture of one of his or her arms or shoulders. Very rarely, it can cause brain damage if the blood supply to your baby's brain is blocked off for too long.

Your baby may have low blood sugar (hypoglycaemia) after birth. This is because he or she makes extra insulin to respond to your high blood sugar levels. Shortly after birth, your baby may continue to make extra insulin causing his or her blood sugar level to be too low.

It's recommended that you breastfeed your baby within 30 minutes of delivery to keep his or her blood sugar levels at a safe level. Otherwise, your baby may be given a sugar solution through a drip (directly into a vein). Midwives or doctors will check your baby's blood sugar level regularly.

Your newborn baby is at risk of jaundice (yellowing of the skin and whites of the eyes). This usually fades without the need for medical treatment. However, sometimes your baby may need treatment with a special ultraviolet light after being born.

There is a higher likelihood that your baby will be born with a birth defect. Sometimes, babies can be born with respiratory distress syndrome, in which the baby has problems breathing because his or her lungs haven't developed as they should. This usually clears up with time, although it may mean that your baby needs to be ventilated with a machine.

There is also a slightly higher chance of stillbirth or death as a newborn, but this is rare as long as blood sugar levels in both you and your baby are well controlled.

There is an increased risk of your baby becoming obese as a child and an increased risk of him or her developing diabetes during childhood.

Causes of diabetes in pregnancy

It's not yet known why some women develop gestational diabetes and others don't, but you're more at risk if you:

• have a family history of gestational diabetes (ie your mother, grandmother or sister had it)
• have previously given birth to a large baby, weighing over 4.5kg (9lb)
• are overweight or obese
• have polycystic ovary syndrome (PCOS)

Women whose families originate from certain areas are also at a higher risk. These include women from South Asia (specifically India, Pakistan or Bangladesh), the Middle East (specifically Saudi Arabia, United Arab Emirates, Iraq, Jordan, Syria, Oman, Qatar, Kuwait, Lebanon or Egypt) and black Caribbean women

Diagnosis of diabetes in pregnancy

Gestational diabetes can be diagnosed using a glucose tolerance test, which is carried out in the morning, after you have eaten nothing overnight. Your doctor will give you a solution of glucose to drink and take blood samples at different intervals to see how your body deals with the glucose over time.

If you're at risk of developing diabetes in pregnancy, you will be offered a glucose tolerance test by your doctor or midwife between 24 and 28 weeks. If you have had gestational diabetes before, you will be offered a test at 18 weeks, and another one at between 24 and 28 weeks if the first is normal.

Treatment of diabetes in pregnancy

Your GP will refer you to a clinic where the doctors and nurses are experienced in looking after pregnant women with diabetes. You will need to have more frequent antenatal appointments than women who don't have gestational diabetes.

Self-help

It's important that you control your blood sugar level. Most women can control it through a carefully planned diet and regular exercise.

Your doctor or a dietitian will be able to give you advice on what to eat. An important part of your diet will be to eat plenty of slowly absorbed carbohydrates such as wholemeal bread and pasta, oats, brown rice, potatoes, lentils and beans. These types of food have a low glycaemic index (GI) and can help even out blood sugar levels when you have diabetes.

Your meal plan will probably consist of these slow absorbing carbohydrates and a variety of lean proteins such as oily fishy, as well as at least five portions of fruit and vegetables each day. You can still eat the odd chocolate bar or packet of crisps but you need to make sure it's all part of a healthy, balanced diet low in fat, sugar and salt.

Regular moderate intensity exercise, such as walking or cycling, helps to reduce blood sugar levels and promote a sense of wellbeing. At least 30 minutes of activity that gets you slightly breathless each day is recommended by the Department of Health.

You will need to regularly test your blood sugar levels. Your doctor at the specialist clinic will give you advice on how to test your blood sugar level, how often to do it, and the levels that you're aiming for. You will probably need to do a test every day.

Medicines

Around one to two women out of 10 won't be able to control their gestational diabetes with diet and exercise and will need insulin injections or tablets. Your doctor or a specialist nurse will teach you how to use injections, or when to take tablets if necessary.

It's possible to have too much insulin and this can cause low blood sugar (hypoglycaemia - sometimes called a 'hypo'). Common symptoms of this are paleness, shaking, hunger and sweating. Your doctor or specialist nurse will explain how to recognise the symptoms of hypoglycaemia, and what to do if it happens. For example, keeping a sugary soft drink handy is a good idea.

Occasionally, low blood sugar can cause you to lose consciousness, and you will need an injection if this happens.

It's a good idea for your family and friends to know what to do if your blood sugar gets very low and you pass out.

After your baby is born

You and your baby will have your blood sugar levels monitored after he or she has been born to make sure they are back to normal.

Doctors recommend that it's best to breastfeed your baby within 30 minutes of delivery to keep your baby's blood sugar levels at a safe level and then every two to three hours.

If you were taking any medication for diabetes, you can stop these after your baby is born. You will be given a blood sugar test at your six-week check-up.

Prevention of type 2 diabetes

Healthy lifestyle choices reduce the risk of you getting type 2 diabetes if you have had gestational diabetes. Aim to eat a balanced diet, take regular exercise and maintain the correct weight for your height.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.