Treatment of diabetes in pregnancy

(Date: September 2017. Version: 1)

This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by the UK Health Security Agency (UKHSA) on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.

What is diabetes?

Diabetes is a condition in which the blood sugar levels are too high. This can have serious effects on the body, both in the short- and long-term.

In type 1 diabetes, the body no longer produces the hormone insulin which regulates blood sugar levels. Treatment of type 1 diabetes is with injected insulin.

In type 2 diabetes, insulin is still produced but the body doesn’t respond to insulin appropriately. Type 2 diabetes is often linked to obesity and is initially treated with diet and exercise. If this is ineffective, oral medicines that lower the blood sugar (such as metformin) and/or injected insulin may be used.

Gestational diabetes occurs during pregnancy and usually gets better on its own after the baby is born. Treatment of gestational diabetes is the same as for type 2 diabetes.

How can diabetes affect pregnancy?

It is important that women with diabetes diagnosed prior to pregnancy (pre-existing diabetes) maintain good control of their blood sugar levels while attempting to conceive and once pregnant.

Pre-existing diabetes has been linked to an increased chance of birth defects in the baby and the best way to minimise this risk is to maintain good blood sugar control in the first trimester. Gestational diabetes is not thought to increase the chance of birth defects in the baby.

Good blood sugar control throughout pregnancy is also critical to reduce the chance of other adverse pregnancy outcomes. All types of diabetes in pregnancy can increase the chance of the baby being larger than expected, leading to possible complications during delivery and the baby having hypoglycaemia (low blood sugar) after birth, which may require short-term treatment. Diabetes in pregnancy is also thought to increase the chance of miscarriage, stillbirth, premature birth, and death of the baby after delivery. These risks are highest if blood sugar control is poor.

Which diabetes treatments are recommended during pregnancy?

It is essential that women with type 1 diabetes continue insulin treatment during pregnancy. Insulin does not cross the placenta and is safe in pregnancy.

Women with type 2 diabetes who are planning to conceive may be advised to attempt to control their condition with diet and exercise. If oral medication is required to control type 2 diabetes, either while attempting conception or during pregnancy, metformin is advised as the first choice. Women taking oral diabetes medicines other than metformin may therefore be advised to switch. If insulin is required, this is considered safe for use in pregnancy.

Women with gestational diabetes will likely be advised to first try and control the condition with diet and exercise before metformin or insulin are offered.

Ideally, women with diabetes should discuss their medication requirements with their doctor prior to conception. Diabetic women with an unplanned pregnancy should contact their doctor as soon as possible.

Can use of diabetes treatments in pregnancy harm my baby?

A baby’s body and most internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that some medicines are known to cause birth defects. There is no proof that treatment with insulin or metformin during pregnancy causes birth defects in the baby, or any other adverse pregnancy outcomes. In fact, because the adverse pregnancy outcomes that are linked to diabetes have a higher chance of occurring where blood sugar control is poor, use of these medicines has been shown to reduce the risk of some adverse pregnancy outcomes.

Will I or my baby need extra monitoring during pregnancy?

As part of their routine antenatal care, most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects and to check the baby’s growth.

Women with diabetes will receive additional monitoring during pregnancy, including blood tests to measure blood sugar control, eye checks, and extra scans to assess the growth of the baby and amniotic fluid levels.

Are there any risks to my baby if the father has diabetes?

We would not expect any increased risk to your baby if the father has diabetes and/or used a diabetes treatment before or around the time you became pregnant.

Who can I talk to if I have questions?

If you have any questions regarding the information in this leaflet please discuss them with your healthcare provider. They can access more detailed medical and scientific information from

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General information 

Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks.  They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.

Medicines use in pregnancy

Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby.  There are, however, some medicines that can harm a baby’s normal development.  How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.

If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.

When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.   

Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.

Disclaimer: This information is not intended to replace the individual care and advice of your health care provider. New information is continually becoming available. Whilst every effort will be made to ensure that this information is accurate and up to date at the time of publication, we cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes following decisions made on the basis of this information. We strongly advise that printouts should NOT be kept for any length of time, or for “future reference” as they can rapidly become out of date.

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