(Date: May 2020. 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 are they?

The macrolides are a group of antibiotics used to treat a wide range of infections. Individual macrolides include azithromycin, clarithromycin, erythromycin, spiramycin and telithromycin.

Erythromycin is the most commonly prescribed macrolide during pregnancy. For specific information on erythromycin use, please see the bump leaflet on Use of erythromycin in pregnancy.

Little information is available on spiramycin and telithromycin with regard to pregnancy.

What are the benefits of using a macrolide in pregnancy?

Macrolides, in particular erythromycin, are used to treat infection and are commonly prescribed during pregnancy.

Are there any risks of using a macrolide during pregnancy?

There are no major concerns with use of macrolides (particularly erythromycin) in pregnancy. Overall, most studies are reassuring, and most doctors agree that the benefits to both mother and baby of treating infection outweigh any possible risks. 

Most studies of women who took macrolides provide no evidence of a link with birth defects in the baby. For the small number of studies that have found a possible link with birth defects, problems with the way in which the information was collected may have led to inaccurate analysis.

The majority of studies of women who took macrolides in early pregnancy also provide no evidence of a link with miscarriage.

There are no concerns that macrolides are linked to stillbirth, preterm birth or low birth weight. However, only small numbers of women have been studied for these outcomes.

Are there any alternatives to using a macrolide in pregnancy?

Possibly. Other types of antibiotic can be used in pregnancy. However, the choice of antibiotic will be based on the type of infection and whether you have had side effects from antibiotics in the past. If you have any questions about a medicine that you are offered in pregnancy, you should discuss them with your doctor or midwife.

What if I prefer not to take medicines during pregnancy?

Treatment of infection during pregnancy is important. If left untreated, infection can make you and your baby seriously unwell. It is therefore important to take antibiotics that have been prescribed for you. You can feel reassured that these medicines are commonly used. Your doctor will only prescribe medicines when absolutely necessary and will be happy to talk to you about any concerns that you might have.

Will my baby need extra monitoring?

As part of their routine antenatal care most women will be offered a detailed scan at around 20 weeks of pregnancy to check the baby’s wellbeing.
Taking a macrolide during pregnancy is not expected to cause any problems that would require extra monitoring of your baby. 

Are there any risks to my baby if the father has taken a macrolide?

We would not expect any increased risk to your baby if the father took a macrolide 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 www.uktis.org

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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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