Diabetes is a condition in which the amount of sugar (glucose) in the blood is too high. Glucose comes from the digestion of starchy foods, such as bread and rice. Insulin, a hormone produced by your pancreas, helps your body to use glucose for energy.
Three types of diabetes can affect you when you're pregnant. Type 1 and type 2 diabetes are long-term conditions that women may have before they get pregnant (pre-existing diabetes). Gestational diabetes develops only in pregnancy and goes away after the baby is born.
Most women with diabetes have a healthy baby, but diabetes does give you a higher risk of some complicataions.
Type 1 diabetes
Type 1 diabetes develops when your body can't produce any insulin. It usually begins in childhood, and most women with type 1 diabetes will be aware of their condition before they become pregnant. People with type 1 diabetes need to take insulin to control their blood glucose.
Type 2 diabetes
Type 2 diabetes develops when your body can't produce enough insulin, or when the insulin that is produced doesn't work properly. It often occurs in overweight people and is usually diagnosed in women aged 40 or over. However, it can happen at a younger age, particularly in black and Asian people.
You may be aware that you have type 2 diabetes before you become pregnant, or you may be diagnosed during your pregnancy. Type 2 diabetes can usually be treated with tablets to lower blood glucose, but some pregnant women require insulin injections.
Gestational diabetes only occurs in pregnancy. It can occur at any stage of pregnancy, but is more common in the second half. It occurs when your body can't produce enough extra insulin to meet the demands of pregnancy. Gestational diabetes goes away after you've given birth.
It's important to know that you're twice as likely to develop type 2 diabetes later in life if you have gestational diabetes when you're pregnant.
Having diabetes when you're pregnant can put you and your baby at risk of complications (see below). You can reduce this risk, but it partly depends on what type of diabetes you have.
If you already have diabetes
If you already have type 1 or type 2 diabetes, you may be at a higher risk of:
having a large baby – which increases the risk of a difficult birth, having your labour induced or a caesarean section
having a miscarriage
People with type 1 diabetes may develop problems with their eyes (called diabetic retinopathy) and their kidneys (diabetic nephropathy), or existing problems may get worse.
Your baby may be at risk of:
not developing normally and having congenital abnormalities – particularly heart and nervous system abnormalities
being stillborn or dying soon after birth
having health problems shortly after birth (such as heart and breathing problems) and needing hospital care
developing obesity or diabetes later in life
Reducing the risks if you have pre-existing diabetes
The best way to reduce the risk to your own and your baby's health is to ensure that your diabetes is controlled before you become pregnant. Ask your GP or diabetologist (diabetes specialist) for advice. You should be referred to a diabetic pre-conception clinic for support before you try to get pregnant.
Find diabetes support services near you.
You should be offered a blood test called an HbA1c test, which helps to assess the level of glucose in your blood. It's best if the level is no more than 6.5% before you get pregnant, as long as this does not cause problems with hypoglycaemia. If your HbA1c is higher than this, you would benefit from getting your blood glucose under better control before you conceive, to reduce the risk of complications for you and your baby. Your GP or diabetes specialist can advise you on how best to do this.
If your HbA1c is very high (above 10%), your care team should strongly advise you not to try for a baby until it has fallen.
Women with diabetes should take a higher dose of folic acid. The normal daily dose for women trying to get pregnant and for pregnant women is 400 micrograms.
Diabetic women should take 5 milligrams (mg) a day. Your doctor can prescribe this high-dose folic acid for you, as 5mg tablets are not available over the counter. Taking folic acid helps to prevent your baby from developing birth defects, such as spina bifida. You should take folic acid while you are trying to get pregnant, until you are 12 weeks pregnant.
Your diabetic treatment regime is likely to need adjusting during your pregnancy, depending on your needs. If you take drugs for conditions related to your diabetes, such as high blood pressure, these may have to be altered.
It's very important to keep any appointments that are made for you, so that your care team can monitor your condition and react to any changes that could affect your own or your baby's wellbeing.
Expect to monitor your blood glucose levels more frequently during pregnancy. Your eyes and kidneys will be screened more often to check that they are not deteriorating in pregnancy, as eye and kidney problems can get worse. You may also find that as you get better control over your diabetes, you have more hypoglycaemic (low blood sugar) attacks. These are harmless for your baby, but you and your partner need to know how to cope with them.
Diabetic eye screening in pregnancy
If you have pre-existing diabetes (you had diabetes before you got pregnant) you will be offered diabetic eye screening at recommended intervals during pregnancy. This screening test is to check for signs of diabetic eye disease, including diabetic retinopathy.
Everyone with diabetes is offered diabetic eye screening, but screening is very important when you are pregnant, because the risk of serious eye problems is greater in pregnancy.
Diabetic eye screening is strongly recommended in pregnancy. It is part of managing your diabetes, and diabetic retinopathy is treatable, especially if it is caught early. If you decide not to have the test, you should tell the clinician looking after your diabetes care during pregnancy.
If you develop gestational diabetes
You're more likely to develop gestational diabetes if:
you're overweight, with a pre-pregnancy BMI (body mass index) above 30 (use the BMI healthy weight calculator, but note that this calculator is not suitable for use during pregnancy)
you've given birth to a large baby, weighing more than 4.5kg (9.9lb), in the past
you've had gestational diabetes before
you have a parent, brother, sister or grandparent with diabetes
your origin is south Asian, black Caribbean or Middle Eastern
If you're in any of these higher risk categories, you should be offered a test to check for gestational diabetes. You may be given a home testing kit to check your blood glucose levels, or you may be offered an oral glucose tolerance test (OGTT or GTT) at 28 weeks or earlier.
A GTT test is a blood test that's done after a period of not eating. You'll be told how long not to eat for before the test (it's often overnight). You'll then be asked to have a glucose drink and take another blood test two hours later.
If you're diagnosed with gestational diabetes, you're at risk of:
having a large baby – which increases your risk of a difficult delivery, having your labour induced or a caesarean section
Your baby may be at risk of:
health problems shortly after birth (such as heart and breathing problems) and needing hospital care
developing obesity or diabetes later in life
Controlling gestational diabetes
Gestational diabetes can often be controlled by diet. A dietitian will advise you on how to choose foods that will keep your blood sugar levels stable. You'll also be given a kit to test your blood glucose levels. If your blood sugar levels are unstable, or your baby is shown to be large on an ultrasound scan, you may have to take tablets or give yourself insulin injections.
Whatever type of diabetes you have, you will have more frequent – and sometimes long – antenatal appointments to check you and your baby's progress. You will be offered advice on diet and treatments tocontrol your blood glucose levels.
Labour and birth
If you have diabetes, it's strongly recommended that you give birth with the support of a consultant-led maternity team in a hospital.
Babies born to diabetic mothers are often larger than normal. This is because blood glucose passes directly from you to your baby, so if you have high blood glucose levels your baby will produce extra insulin to compensate. This can lead to your baby storing more fat and tissue. This in turn can lead to birth difficulties, which requires the expertise of a hospital team.
After the birth
Two to four hours after your baby is born, they will have a heel prick blood test to check whether their blood glucose level is too low. Feed your baby as soon as possible after the birth (within 30 minutes) to help keep your baby's blood glucose at a safe level.
If your baby's blood glucose can't be kept at a safe level, they may need extra care. Your baby may be given a drip to increase their blood glucose.
When your pregnancy is over, you won't need as much insulin to control your blood glucose. You can decrease your insulin to your pre-pregnancy dose or, if you have type 2 diabetes, you can return to the tablets you were taking before you became pregnant. Talk to your doctor about this.
If you had gestational diabetes, you can stop all treatment after the birth. You should be offered a test to check your blood glucose levels before you go home and at your six-week postnatal check. You should also be given advice on diet and exercise.