Diabetes mellitus is a condition when the body does not have enough insulin to deal with the sugar in your blood.

There are three types of diabetes that affect pregnancy, and they all are treated in different ways.

  • Type 1 Diabetes – This type starts in childhood or adolescence and is caused by the failure of the pancreas to produce insulin. Women who have this will have been on insulin injections for a long time.
  • Type 2 Diabetes – This type of diabetes is due to resistance to insulin. It can be due to a family history or obesity. In general, it can be treated with diet or by tablets.
  • Gestational Diabetes – This occurs only in pregnancy and can be either controlled by diet, tablets or insulin injections. The treatment is different for each individual and is managed by a specialist team.

Type 1 Diabetes

One of the most important times for a woman with diabetes, is the planning stage of getting pregnant. It is important to have good control over your blood sugar levels in the lead up to pregnancy. By doing this it improves the chance of getting pregnant, reduces the chance of miscarriage and reduces the chance of any abnormalities in the baby. In the longer term, it prepares the way for a healthier pregnancy and lower complication rate.

Most women with type 1 diabetes will have regular scans for growth and fluid levels to make sure the baby is not growing too quickly (a sign of poor sugar control). The team will tend to want you to be delivered at about 38 weeks of pregnancy, although this does depend on the unit that you are booked at and the clinical situation at the time.

Type 2 Diabetes

In a similar manner to those women with type 1 diabetes, control of blood sugar prior to pregnancy is a vital time. A lot of women with type 2 diabetes are overweight and pre-pregnancy is the ideal time to prepare for pregnancy by losing weight. This will allow the pregnancy to be a much healthier and happier time with a lower risk of complications.

Losing weight prior to pregnancy will improve your chance of falling pregnant, reduce the chance of miscarriage, reduce the risk of abnormalities in the baby, improve your health in the pregnancy, improve your sugar control during the pregnancy, and reduce the chance of pregnancy and birth complications.

Extra growth and fluid scans may be offered and, depending on growth and sugar control, your team may want you to have your baby delivered early (although this is dependent on the unit policy, your sugar control, baby’s growth and other clinical factors).

Gestational Diabetes

This type of diabetes occurs only in pregnancy. Women who have this are not diabetic before pregnancy, but develop it during the pregnancy. It usually disappears after pregnancy. Women who develop gestational diabetes have a greater chance of developing diabetes later in life.

There are several types of people who are at a higher risk of gestational diabetes and they should all be offered a diabetes test.

  • Women who have had gestational diabetes in a previous pregnancy
  • Overweight (BMI >30)
  • Any minority ethnic family origin with a high prevalence of diabetes
  • A strong family history of diabetes
  • If you have had a previous large baby (>4.5kgs)

Treatment of gestational diabetes is much more variable. Some women can manage it with diet alone, others need tablets, whilst some need insulin. The team who cares for women with diabetes in pregnancy at your unit will keep a very close watch on your pregnancy and advise you regarding scans and time for delivery.

Gestational diabetes affects up to 5% of all pregnancies. The risk of developing type 2 diabetes later in life after developing gestational diabetes is 30%.

Watch these videos produced by North West London Maternity:

Risks to mums with Diabetes

The main risks are directly related to high blood sugar levels, although some risks are higher, even if you manage your sugar levels carefully.

  • Fetal abnormality – Women with pre-existing diabetes are more likely to have a baby with an abnormality. If their diabetes is poorly controlled pre-pregnancy, then the risks are even higher. This is the reason for being really careful with your control prior to getting pregnant and planning your pregnancy very carefully.
  • Miscarriage – As per fetal abnormality
  • Stillbirth – Women with diabetes have a higher risk of stillbirth than the general population. If your control is poor, the risk is higher than if your sugar control is good.
  • Large baby – This is due to the high sugar levels in your blood which pass across to your baby. This leads to your baby having high insulin levels, which causes your baby to grow in size.
  • High blood pressure – Pre-Eclampsia is more common in women with diabetes, especially those who are overweight, have pre-existing high blood pressure or kidney problems.
  • Labour problems – Women with poorly controlled diabetes are more likely to end up with an emergency caesarean section, primarily because of a larger baby and the need for Induction of Labour (IOL). In some cases, IOL could have been avoided if diabetic control had been better during the pregnancy.

Risks to babies of mums with Diabetes

  • Breathing problems – Babies born to mums with diabetes are more likely to have breathing difficulties at birth, especially if they are born by caesarean section or prematurely.
  • Low blood sugar – During pregnancy, the baby will have a constant supply of sugar. In diabetic mums, this is higher than average. The baby gets used to producing insulin of its own, but, when it is born, the sugar supply disappears. Unfortunately, the insulin level carries on at a high level, giving the baby a low blood sugar.
  • Big baby – Medically this is known as “Macrosomia”. Big babies are more likely to get stuck during birth and are more likely to have low blood sugars after delivery. They are also more likely to have other illnesses after birth too.


The most important points if you have diabetes are:

  • Planning your pregnancy carefully (women with pre-existing diabetes)
  • Careful diet (low sugar foods)
  • Aim to keep your blood sugar levels as close to ‘normal’ as possible
  • Monitoring your babies movements closely
  • Keep all your hospital appointments