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Diabetes in pregnancy

Diabetes that develops in pregnancy is called gestational diabetes. It occurs as a result of your body being unable to produce enough insulin to meet the increased need in pregnancy. Most women who develop diabetes in pregnancy have a normal healthy pregnancy.


Who has a higher chance of developing diabetes in pregnancy?

Any women can develop gestational diabetes, however you are at an increased risk if:

  • your body mass index (BMI) is above 30 
  • You have polycystic ovary syndrome (PCOS)
  • you previously had a baby who weighed 4.5kg (10lb) or more at birth
  • you had gestational diabetes in a previous pregnancy
  • one of your parents or siblings has diabetes
  • you are of south Asian, Black, African-Caribbean or Middle Eastern origin (even if you were born in the UK)


Screening for gestational diabetes

If you have a higher chance of developing diabetes in your pregnancy you will be screened  using a glucose tolerance test (GTT) when you are between 24-28 weeks pregnant. A GTT involves fasting overnight (not eating or drinking anything apart from water):

• In the morning, before breakfast, you will have a blood test. You are then given a glucose drink.

• The blood test is repeated 1–2 hours later to see how you body reacts to the glucose drink.  


Caring for women with gestational diabetes

If you do have diabetes in pregnancy you will be looked after by a specialist diabetes team. This will include a diabetologist, obstetrician, diabetes nurse or midwife and dietician. You will also be advised to have some extra scans during pregnancy to check the growth of your baby. Although some women who develop gestational diabetes can control their blood sugars by making changes to their diet, it is quite common to need to take other medication. This might include tablets and/or injections. You will also be advised to measure and record your own blood sugars using a finger prick test. There will be several appointments at the hospital and you will be given the telephone contact details of someone from the team, who you can contact if you have any concerns or need further advice. Slightly earlier delivery of your baby may be advised, depending on how your pregnancy has progressed. This is normally by induction of labour, this will of course be discussed with you so that you are fully informed of the reasons for this and the range of options available to you.


Women with pre-existing diabetes (Type 1 or 2)

Women with pre-existing diabetes (Type I or Type 2) get the best chance of a healthy pregnancy, birth and postnatal period if their diabetes is well controlled before birth. There are some precautions you can take to ensure that you and your baby remain as safe as possible.

If you have pre-existing diabetes you should talk to your diabetes team to stabilise your diabetes before you try and conceive. Ideally we like your HbA1c (a test that looks at average sugar control over a period of a few months) to be lower than 48mmol/l. By having tight control of your sugars you can significantly reduce your chance of complications of pregnancy, such as miscarriage, stillbirth, congenital malformation, birth trauma (to mother and baby), fetal macrosomia (excessively large baby), increased early intervention, perinatal mortality, worsening retinopathy (eyesight problems) or nephropathy (kidney problems), obstetric complications and the risk of inheritance of diabetes. If your diabetes control has been problematic, you may be advised to try and control your diabetes better before you consider coming off contraception. This will generally be the case if your HbA1c is greater than 86mmol/l.

Women with pre-existing diabetes will also be advised to take a higher dose (5mg) of folic acid starting from 3 months before you stop contraception. This dose needs to be prescribed by a doctor (your GP or diabetologist). This reduces your chance of having a baby with spina bifida. It may also be necessary to change other medication you are taking in order to reduce the chance of pregnancy complications. You will be advised to take low dose aspirin (150mg) from 12 weeks gestation until birth as this can reduce the chance of you developing blood pressure problems later in the pregnancy.


Your emotional wellbeing

It is really important that you look after your own mental wellbeing when pregnant. Sometime this may feel challenging amongst additional appointments, scans and checks. See here for more information about looking after you and the support available.


After your baby is born

Babies of mothers with diabetes should stay with their mothers unless there is a clinical complication. The most common complication in babies is hypoglycaemia (low blood sugar), however, hypocalcaemia (low blood calcium), polycythaemia (increased red cells in the blood), cardiomyopathy (functional heart problems) and respiratory distress syndrome (RDS) are also seen, particularly if diabetes control in pregnancy has been suboptimal. Hypothermia predisposes to hypoglycaemia and should be avoided. If your baby shows signs of developing any complications, we may need to provide closer observation and treatment of your baby in our Neonatal Unit .

Breastfeeding your baby can help reduce the chance of your child developing diabetes and/or obesity in later life. Woman who develop gestational diabetes are at increased chance of developing Type 2 diabetes later in life. If you do develop gestational diabetes you can reduce your chance of this happening by breastfeeding and keeping to a healthy weight throughout your life.

Useful leaflets

Gestational diabetes in pregnancy

Healthy eating with gestational diabetes

Insulin use in pregnancy

Managing Type 1 and Type 2 diabetes in pregnancy

Contraception for women with diabetes

Diabetes UK prescription chart

Colostrum harvesting

Perineal massage

Healthier for You national diabetes prevention programme

Further sources of information