Gestational diabetes

Gestational diabetes is a temporary form of diabetes that develops during pregnancy. It is high amounts of sugar in the blood but this usually returns to normal after giving birth.

Gestational diabetes develops when the body doesn’t produce enough insulin for the extra needs of pregnancy. Insulin is a hormone that helps control blood sugar levels.

It can occur at any stage of pregnancy but is more common in the second half.

Most cases are discovered when blood sugar levels are tested during antenatal screening but some people can experience symptoms.

You will be offered extra care and support to manage the diabetes and reduce any risks for your baby.

Being diagnosed with gestational diabetes can bring extra feelings of responsibility, financial constraint or conflict with cultural practices, as diet and lifestyle may need to be adjusted. It could also be seen as an opportunity to make positive lifestyle changes and healthy eating choices.

Often gestational diabetes has no obvious symptoms. Most cases are picked up when blood sugar levels are tested during antenatal checks.

Some pregnant women may develop symptoms if their blood sugar level gets too high, like:

• being more thirsty than usual
• a dry mouth
• weeing more often than usual
• tiredness

Some of these can be common symptoms during pregnancy, so aren't necessarily a sign of gestational diabetes. Do speak to a midwife or GP if you're worried.

Some women are more likely than others to get gestational diabetes in pregnancy. A person has a higher risk if:

• their body mass index (BMI) was higher than 30 before the pregnancy.
• they have previously given birth to a large baby weighing 4.5kg (10lb) or more.
• they had gestational diabetes in a previous pregnancy.
• they have a family history of diabetes; for example, a parent or a brother or sister has diabetes.
• their family’s ethnicity is south Asian, Black, African-Caribbean or Middle Eastern.
• they have polycystic ovaries.

A midwife or GP will ask about these risk factors at the first antenatal appointment – at around eight to 12 weeks of pregnancy. Individuals will be offered a test for gestational diabetes if any of these risk factors apply.

This is called a glucose tolerance test (gtt) which is normally offered at 26 weeks of pregnancy. However, if you have suffered with gestational diabetes previously then you may be offered the test earlier at around 16 weeks.

Most women who develop diabetes in pregnancy have healthy pregnancies and healthy babies.

Occasionally, gestational diabetes can cause problems like:

• The baby being bigger than usual, which may lead to complications during birth and so increase the likelihood of an induced labour or caesarean.
• Too much amniotic fluid around the baby (polyhydramnios).
• It may cause the baby to be born prematurely.
• It could be linked to pre-eclampsia – a condition that causes high blood pressure during pregnancy and can cause pregnancy complications if not treated.
• The baby could develop low blood sugar after birth, or yellowing of the skin and eyes (jaundice) after they are born, which may require treatment in hospital.
• Stillbirth – although this is extremely rare.

Controlling blood sugar levels during pregnancy reduces the risk of complications. This can be done through healthy eating and regular exercise. Some people may also need medication if lifestyle changes don’t make enough difference to their blood sugar levels.

It’s particularly important for people with gestational diabetes to focus on the type and amount of carbohydrates in their diet. A midwife or GP can advise about choosing foods with a low glycaemic index (GI). These foods will help to keep blood sugar levels at a healthy and stable level. People with gestational diabetes should be referred to a dietician.

Physical activity also lowers blood glucose levels. A midwife or GP will provide guidance about the different ways of keeping active – like walking for 30 minutes after a meal. It’s good to aim for around two and a half hours of moderate exercise a week plus strength exercises on two or more days a week.

With gestational diabetes, a diabetes multidisciplinary healthcare team will monitor the pregnancy and birth more closely. This makes sure that the risk of any problems as a result of diabetes is reduced.

Someone with gestational diabetes will:

• be asked to check their blood sugar levels several times a day.
• have a midwife provide them with a blood sugar testing kit and be shown how to use this correctly.
• have a discussion with a midwife about how often to test blood sugar levels and what the ideal blood sugar level is.

More appointments

More appointments will be offered with a midwife and multidisciplinary diabetes team to monitor the baby’s health and wellbeing.

Extra ultrasound scans

Extra scans will be offered to check how the baby is growing. By checking their size, your midwife and/or GP can discuss the best options for giving birth.

Gestational diabetes can cause problems during pregnancy and after birth, but the risks can be reduced if the condition is detected early and managed. One study showed that pregnant women who control gestational diabetes through their diet and whose babies are growing normally may be considered at low risk

Your midwife or GP will discuss with you the timing for giving birth and where to have your baby.
It will be recommended that birth takes place before 40+6 weeks in a hospital, or earlier if there are concerns about the pregnant person or baby’s health, or if blood sugar levels are not well controlled.

If your baby has not been born by this time, they will offer induction of labour or a caesarean birth.
Caesarean birth may be advised if your baby is estimated to be very large (macrosomia) using ultrasound measurements. These measurements are accurate 90% of the time at spotting larger babies but they can overestimate a baby’s actual weight.

Blood sugar levels will be monitored closely during and after labour.

Gestational diabetes usually goes away after your baby is born – when your hormones return to their normal levels.

Blood glucose levels will be tested after giving birth, before leaving hospital and once again at 12 weeks when HbA1C blood test .

After birth, any medicine that was being taken to control blood sugar levels will be stopped and blood sugar levels will be checked the next day.

It is important to feed your baby as soon as possible after birth: within 30 minutes and at frequent intervals (at least every two to three hours) after to help to stabilise their blood sugar levels.

Your baby’s blood sugar level will be tested between two to four hours after birth and, if it is low, your doctors may recommend that your baby is fed through a tube or drip temporarily.

If a baby needs more specialised care, they may be looked after in a specialist neonatal unit.

If all the checks go well, the parent and baby will be discharged to go home after 24 hours.

Breastfeeding a baby quickly after birth can help their blood glucose stay at a safe level.
Some parents choose to express and safely store colostrum from week 36 of pregnancy. This colostrum can then be used to supplement feeding a baby after birth. This practice is safe, it may speed up the production of breastmilk after birth, and it is associated with babies breastfeeding for longer. It might also build a parent’s confidence with breastfeeding and make parents feel prepared for their baby’s arrival.

Breastfeeding for three months or more might reduce the risk of developing type 2 diabetes later in life for the parent.

People who have had gestational diabetes are more likely to develop the condition in a future pregnancy. So, it’s important to talk to a GP when planning future pregnancies.

It is also more likely that someone may develop type 2 diabetes later in life if they have had gestational diabetes. The risk is higher in the four to five years after having gestational diabetes. It’s important to talk to your GP about what can reduce this risk and seek medical advice if any symptoms of diabetes develop.

An annual blood glucose test (HbA1C) may be offered to anyone who has had gestational diabetes.

If you have any concerns, contact your midwife or GP.