Macrolide antibiotics

(Date: June 2017. Version: 2.1)

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 Public Health England 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.

Feedback request 

WE NEED YOUR HELP! Do you have 3 minutes to complete a short, quick and simple 12 question user feedback form about our bumps information leaflets? To have your say on how we can improve our website and the information we provide please visit www.surveymonkey.co.uk/r/uktis-bumps.

What are they?

The macrolides are a group of antibiotics that are used to treat a wide range of infections. Individual macrolide antibiotics 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.

Is it safe to use a macrolide in pregnancy?

The timely and correct treatment of potentially severe bacterial infections during pregnancy may be crucial to the health of both mother and baby.

When deciding whether or not to take a macrolide antibiotic during pregnancy it is important to weigh up how necessary this is to your health against the possible risks to you or your baby, some of which will depend on how many weeks pregnant you are. Your doctor is the best person to help you decide what is right for you and your baby.

What if I have already taken a macrolide during pregnancy?

It is always a good idea to let your doctor know that you are pregnant if you have taken any medicines in case you need any additional monitoring or treatment.

This leaflet summarises the scientific studies relating to the effects of macrolide antibiotics on a baby in the womb.

Can taking a macrolide in pregnancy cause my baby to be born with birth defects?

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.

Studies which together included babies of over 4,000 pregnant women who took a macrolide antibiotic in early pregnancy found that birth defects were no more common than in babies of women not taking macrolides. Four studies have also all shown no link between taking a macrolide antibiotic in pregnancy and the baby having a heart defect.

Some studies have assed specific macrolide antibiotics individually (rather than as a combined group). These studies found no link between taking azithromycin, clarithromycin, or erythromycin in pregnancy and the occurrence of birth defects generally in the baby, or of heart defects specifically.

Can taking a macrolide in pregnancy cause miscarriage?

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.

Six studies that together include over 35,000 women who took any macrolide in early pregnancy provide no evidence of links with birth defects in the baby in general. Five studies also found no links with heart defects in the baby.

Four studies that together include over 1,700 women who took azithromycin in early pregnancy provide no evidence of links with birth defects in the baby in general. Three of these studies also found no links with heart defects in the baby.

Four studies that together include over 1,600 women who took clarithromycin in early pregnancy provide no evidence of links with birth defects in the baby in general. Three of these studies also found no links with heart defects in the baby. A single study also found no evidence that exposure to clarithromycin in the womb can cause defects of the limbs or external genitals in the baby.

A single study provided no evidence of a link between spiramycin use in early pregnancy and birth defects in the baby in general. Further research is required to confirm this finding.

No studies have investigated the occurrence of birth defects in babies exposed in the womb to telithromycin.

Overall, there is no evidence that exposure to macrolides in early pregnancy is linked to birth defects in general, or heart defects in the baby. Further research into the occurrence of other specific birth defects, and following use of spiramycin and telithromycin is ideally required.

Can taking a macrolide in pregnancy cause miscarriage?

Although a single study did find a possible link between miscarriage and use of any macrolide in early pregnancy, three further studies that include over 700 pregnant women taking macrolides have found no link.

Two studies of a total of over 8,000 women taking azithromycin in early pregnancy reached different conclusions, with one finding no link with miscarriage, and the other finding that women taking azithromycin had a higher chance of miscarriage than women taking either no antibiotics or a different type of antibiotic. However, this study was not able to rule out that the higher chance of miscarriage was actually due to more severe infections in the mothers who took azithromycin, and further studies should ideally take this into account.

Three studies of a total of over 8,000 women taking clarithromycin in early pregnancy all found a possible link with miscarriage. However, in at least two of these studies, there were problems in the way that the information was collected and analysed. Further well-designed research is therefore required before we can say whether use of clarithromycin in early pregnancy may increase the chance of miscarriage.

Further well-designed research into the occurrence of miscarriage following use of clarithromycin, azithromycin, spiramycin, and telithromycin in pregnancy is required before conclusions can be drawn. However, serious infections in pregnancy can severely compromise the health of both the mother and the unborn baby, and this should be borne in mind when the risks and benefits of antibiotic use in pregnancy are being considered.

Can taking a macrolide in pregnancy cause stillbirth?

One small study provided no evidence of a link between stillbirth and use of clarithromycin in pregnancy. No further studies have investigated the occurrence of stillbirth following use of macrolides in pregnancy, and further research into this subject is therefore required.

Can use of a macrolide in pregnancy cause preterm birth?

Three studies of a total of over 500 women using macrolides in pregnancy all found no link with preterm birth. More research is ideally required to confirm this finding, and information on individual macrolides is also required.

Can use of a macrolide in pregnancy cause my baby to be small at birth (low birth weight)?

Four studies of a total of over 600 women using macrolides in pregnancy all found no suggestion that use was linked to reduced birth weight in the baby, and a single study on azithromycin produced similar results. More research specifically into the occurrence of low birth weight (<2,500 g) is however, required, as is information on other individual macrolides.

Can taking a macrolide in pregnancy cause learning or behavioural problems in the child?

A baby’s brain continues to develop right up until the end of pregnancy. It is therefore possible that taking certain medicines at any stage of pregnancy could have a lasting effect on a child’s learning or behaviour.

Studies that have investigated whether children who were exposed in the womb to macrolides are at increased risk of learning and behavioural problems compared to children not exposed to antibiotics have produced mixed findings. However, most of these studies were of antibiotic use in women who had gone into premature labour. Preterm birth has itself been linked to an increased risk of learning and behavioural problems in children. It is therefore likely that the effects seen in some studies may have been due to the prematurity of the baby, or infections in the mother that may have caused premature labour, rather than to macrolide use by the mother during pregnancy. Further research into this subject is therefore required.

Will 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.
  
There is no evidence that taking a macrolide during pregnancy causes 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 health care provider. They can access more detailed medical and scientific information from www.uktis.org.

Feedback request 

WE NEED YOUR HELP! Do you have 3 minutes to complete a short, quick and simple 12 question user feedback form about our bumps information leaflets? To have your say on how we can improve our website and the information we provide please visit www.surveymonkey.co.uk/r/uktis-bumps.

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.

   

www.medicinesinpregnancy.org

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.

My bump’s record

Create your own ‘My bump’s record’.

Provide information about your pregnancy to help women in the future.

Login to my bumps

Join my bumps