Overview
Gestational diabetes is high blood sugar (glucose) that develops during pregnancy. It is most often found in the second or third trimester, and it usually goes away after the baby is born.
It happens when the body cannot make enough to meet the extra needs of pregnancy. Testing and treatment protect both mother and baby.
Symptoms
Most women have no symptoms, and the condition is found by a test. If symptoms do appear, they can include:
- Increased thirst
- Passing urine more often than usual
- A dry mouth
- Tiredness
- Blurred vision
- Itching around the genitals, or thrush
These are common in pregnancy anyway, so tell your midwife or doctor if you are worried.
When to see a doctor
See your doctor promptly if you notice strong thirst, a dry mouth or passing urine much more than usual, or if your home sugar readings are above your targets. Do not wait for your next test. If you are planning another pregnancy, or have not had a blood test since your last birth, ask for a diabetes check.
Causes
Hormonal changes in pregnancy make the body's cells respond less well to . If the body cannot make enough extra insulin to make up for this, blood sugar rises.
Risk factors
Any woman can develop gestational diabetes, but it is more likely if you have:
- Age over 40
- A body mass index () above 30
- Gestational diabetes in an earlier pregnancy
- A previous baby weighing 4.5 kg or more at birth
- A parent, brother or sister with diabetes
- South Asian, Black, African-Caribbean or Middle Eastern family origin
- Polycystic ovary syndrome (PCOS)
Complications
These are possible when blood sugar is not controlled:
- A larger than usual baby, which can make the birth harder and induced labour or a caesarean more likely
- Low blood sugar and jaundice in the baby after birth
- Too much fluid around the baby, and early birth
- Pre-eclampsia in the mother
- A higher chance of gestational diabetes next time and of type 2 diabetes later
- Stillbirth, which is rare
Prevention
Gestational diabetes cannot always be prevented. Reaching a healthy weight before pregnancy, eating healthily and being active may help. Once pregnant, do not try to lose weight: ask your doctor how much weight gain is right for you. Before another pregnancy, ask for a diabetes check.
Diagnosis
At the first antenatal visit you are asked about risk factors, and if you have any you should be offered a test. The usual test is the oral glucose tolerance test, which takes about two hours:
- A blood sample after 8 to 10 hours without food
- A sugary drink
- A second blood sample two hours later, while you rest
It is usually done between weeks 24 and 28, or earlier if you have had gestational diabetes before. After the birth, a blood test 6 to 13 weeks later checks that your sugar has returned to normal.
Treatment
The first steps are changes in diet and more activity, with a home kit to check your blood sugar.
- Eating healthy food in sensible amounts at regular times
- Walking, swimming or prenatal yoga, after checking with your doctor
- Tablets or injections, if diet and activity are not enough
You will be watched more closely during pregnancy and the birth. The aim is for the baby to be born before 41 weeks, and induction or a caesarean may be suggested if labour has not started by then, or earlier if there are concerns.
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“I have no symptoms and I feel well, so my sugar must be fine.”What is true?
Fact
Gestational diabetes usually causes no symptoms, and thirst and passing urine often are common in pregnancy anyway. That is why a blood test, usually between weeks 24 and 28, is offered, and why it is worth having.
Myth“Gestational diabetes happens because the mother ate too many sweets.”What is true?
Fact
It happens because the body cannot make enough insulin for the extra needs of pregnancy, partly because pregnancy changes make the body's cells respond less to insulin. Any woman can develop it. It is not a punishment, and some women are more likely to get it, for example those with diabetes in the family.
Myth“Insulin is dangerous, and once you start it you can never stop.”What is true?
Fact
If diet and activity do not bring blood sugar down enough, doctors may prescribe tablets or insulin injections to protect you and your baby. Gestational diabetes usually goes away after the birth, so this treatment is not usually for life.
Myth“A pregnant woman should rest and avoid walking or exercise.”What is true?
Fact
Being more active helps to bring blood sugar down. Walking, swimming and prenatal yoga can help, but check with your midwife or doctor before starting a new activity.
Myth“Once the baby is born, the diabetes is gone and nothing more is needed.”What is true?
Fact
Blood sugar usually returns to normal, but gestational diabetes raises the chance of type 2 diabetes later. A blood test 6 to 13 weeks after the birth, and then every year, is advised even if you feel well.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
Will gestational diabetes harm my baby?
It can cause problems, such as a larger baby, low blood sugar after birth and early birth. Testing and treatment protect both you and your baby, which is why following your plan matters. Tell your team early if you are finding it hard.
Will I need insulin?
Not necessarily. Changes in diet and more activity are the first steps, and if they are enough you will not need medicine. If they do not bring your blood sugar down enough, you will be offered tablets or insulin injections.
Does it go away after the baby is born?
It usually does, and blood sugar usually returns to normal. But you have a higher chance of type 2 diabetes later, and of gestational diabetes in a future pregnancy. A blood test 6 to 13 weeks after the birth, and then every year, is advised even if you feel well.
When will my baby be born?
The aim is a birth before 41 weeks. If labour has not started by then, induction or a caesarean may be recommended. An earlier birth may be advised if there are health concerns or blood sugar is hard to control. Your team will plan this with you.