Risks of type 1 or 2 diabetes on pregnancy

Women with type 1 or 2 diabetes are at higher risk of some complications but the majority have normal pregnancies and healthy babies. There is much you can do to reduce the risks, for you and baby.

When you are pregnant, the pregnancy hormones interfere with the way your body works, which makes it more difficult to control your blood glucose levels. This means that during the pregnancy you have an increased risk of some health problems, such as kidney or eye problems, neuropathy (nerve damage) and vascular disease (problems with the blood vessels). If you already have complications such as eye or kidney problems, these may get worse during the pregnancy. You are also more likely to have low or high blood pressure levels and hypos or hypers, with the extra risks that these carry.

Retinopathy and nephropathy and pregnancy

There are two particular medical conditions associated with diabetes that can worsen during pregnancy: retinopathy (eye problems) and nephropathy (kidney problems).

Both are caused by damage to tiny blood vessels that can be affected by high blood glucose levels and high blood pressure. You will be checked at regular intervals before and through your pregnancy to make sure you are not developing these conditions. Ideally, you will checked before pregnancy to check your level and followed-up during pregnancy to make sure there aren’t any signs of changes that are a concern. If there are concerns, you may be referred to a specialist team.

  • Eye problems (Retinopathy): Is a condition that affects the blood vessels in your eyes, damaging the retina. It can worsen as a result of high blood glucose levels in early pregnancy and high blood pressure. If left untreated, it can cause blurred vision and, ultimately, blindness. Treatments include laser therapy. You’ll be offered screening tests for retinopathy at or soon after your first antenatal clinic visit, and also after 28 weeks. If signs of it are found at the first screening test, you’ll be offered an extra test between weeks 16 and 20. If you are found to be at risk of serious eye problems, you’ll be referred to an eye specialist.
  • Kidney problems (Nephropathy): Is another name for kidney disease. If your kidneys become damaged your body loses its ability to filter out waste products from your blood. If you have nephropathy in pregnancy, this may affect your blood pressure, which can lead to pre-eclampsia.

You are also at a higher risk of:

Your baby will be at higher risk of:

  • macrosomia (large for gestational age, see more on this below)
  • a congenital disorder (4.8% compared with 2.2% for the wider population).
  • stillbirth (around 1.6% compared with 0.5% for the wider population) 
  • dying in the early weeks of life (around 1% compared with 0.3% for the wider population).

Although these risks are real, they are still small and you can reduce them even further by controlling your blood glucose levels.

More about macrosomia

Type 1 or 2 diabetes and macrosomia

Macrosomia is a difficulty associated with diabetes – in which the baby is large for their gestational age, often weighing more than 4.5kg at birth.

This is caused by the mother’s high blood glucose levels transferring across to the baby. The baby then produces more insulin to deal with the high blood glucose levels, which can make them grow larger than normal - especially around the shoulder, chest and abdomen.

The likelihood of this is fairly high – almost half of pregnancies for women with Type 1 diabetes and almost a quarter of those with Type 2 result in babies that are large for gestational age.

This can affect labour and birth in women who have diabetes, increasing the risk of shoulder dystocia – in which there is difficulty delivering the baby’s shoulders after the head has been born. This requires some additional manoeuvres at birth to help the baby out. Your midwife can explain these to you.

If there is delay at this point of labour, your baby may not be able to breathe. Because of this risk, you are more likely to have an assisted birth, induction or caesarean to get the baby out safely. In most cases of shoulder dystocia the baby is born promptly and safely.

Read more: Royal College of Obstetricians and Gynaecologists: shoulder dystocia: (PDF, 223kb)

If your baby has been producing extra insulin, then their blood glucose levels can drop too low soon after birth. Because of this, they need to be fed within 30 minutes after birth and at regular intervals, and their blood glucose levels will need to be monitored. Additional treatments such as tube feeding or IV dextrose treatment may be needed, and they may need to be cared for in a specialist baby unit in the hospital.

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An increased risk does not mean it will happen

Although these risks are real, they are still small and you can reduce them even further by controlling your blood glucose levels.

'Having the risks explained to me was ultimately my motivator to getting blood sugars perfect.' Zoe, mum of one

We understand that it is not easy to read about these risks. But it is important that you know about them so that you can make informed decisions around your pregnancy.

A risk means there is a chance that something might happen. These things may not happen to you. But by knowing what the risks are, it can be easier to understand your healthcare team’s advice.

It may be harder than it sounds, but try to find a balance between understanding the risks while remembering that many women with diabetes have problem-free pregnancies.

Reducing the risks of diabetes complications in pregnancy

If you have diabetes, you will probably already be used to planning carefully to manage your glucose levels – but pregnancy will mean you need to increase the amount of time and effort you need to spend on controlling your diabetes. You will have more healthcare appointments. Friends who do not have diabetes may seem to have comparatively carefree pregnancies while you are monitoring your blood glucose levels and controlling your diet and exercise. If you find this difficult, you are not alone.

But the research shows that taking these extra steps can make a difference to your own health and that of your baby. It’s a lot to take on board, so find support where you can, and try to remember that this period will not last forever. If you want to speak to someone about how you are doing and feeling, try your GP, diabetes team, Diabetes UK (www.diabetes.org.uk) or check out the forums on www.diabetes.co.uk.

Also in this section

More sections on type 1 or 2 diabetes in pregnancy


  1. NCC-WWCH (2015) Diabetes in pregnancy: Management of diabetes and its complications from preconception to the postnatal period NICE guideline 3, Methods, evidence and recommendations, Version 2.1, National Collaborating Centre for Women's and Children's Health
  2. HSCIC (2014) National Pregnancy in Diabetes Audit Report, England, Wales and the Isle of Man 2013, Health and Social Care Information Centre
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    Last reviewed on September 1st, 2015. Next review date February 1st, 2016.

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    Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.

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