Quinolone antibiotics

What are they?

The quinolones are a group of antibiotics that include ciprofloxacin, levofloxacin, moxifloxacin, nalidixic acid, norfloxacin and ofloxacin. Quinolones are used to treat a wide range of infections.

Is it safe to use quinolones in pregnancy?

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

When deciding whether or not to take a quinolone 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 quinolone antibiotic 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 quinolone antibiotics on a baby in the womb. 

You should not alter the dose of any of your medicines without medical supervision. Your doctor is the best person to help you decide what is right for you and your baby.

Can taking a quinolone antibiotic 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.

Four well-designed studies all found that birth defects were no more common in babies born to pregnant women who took a quinolone antibiotic in early pregnancy than in babies of women not taking quinolones. One study that investigated whether use of a quinolone antibiotic in early pregnancy may increase the likelihood of specific types of heart defects found possible links with two types: conotruncal defects and tetralogy of Fallot. Because these study findings were based on small numbers of babies exposed in the womb they require confirmation with further research.

All of the four studies of women specifically using ciprofloxacin, and eight of nine studies of women using norfloxacin, found no increased occurrence of birth defects in their babies. Single studies specifically investigating levofloxacin, moxifloxacin, nalidixic acid and ofloxacin have also not identified any cause for concern, but since their findings are based on fewer women taking these antibiotics, further research is ideally required to confirm these results.

Single studies each found no link between use of ciprofloxacin or nalidixic acid in early pregnancy and heart defects or a number of other different birth defects in the baby. Because each antibiotic has only been investigated in one study, further research is required to confirm these findings.

Can taking a quinolone antibiotic in pregnancy cause miscarriage?

Two studies investigated whether women taking quinolone antibiotics as a group in early pregnancy were at increased chance of miscarriage, with conflicting findings. Further well-designed studies that take into account the effects of underlying infections on the chance of miscarriage are therefore required to answer this question.

Can taking a quinolone antibiotic in pregnancy cause stillbirth?

Two studies found that, when studied as a group, women taking a quinolone antibiotic were no more likely to have a stillbirth than women not taking a quinolone. These were both a type of study called a meta-analysis, which take data from several smaller studies and analyse it together, and are considered a more reliable way to assess the risk of medical events occurring within a population.

There is currently no information on the chance of stillbirth for individual quinolone antibiotics.

Can taking a quinolone antibiotic in pregnancy cause preterm birth?

Four studies have not shown an increased chance of preterm birth in babies exposed in the womb to a quinolone antibiotic. A very small study also found no increased risk of preterm birth in babies exposed in the womb to oxolinic acid (a quinolone that is not available in the UK), however more research is required to confirm this finding. No studies have investigated the chance of preterm birth in babies exposed in the womb to other quinolones.

Can taking a quinolone antibiotic in pregnancy cause my baby to be small at birth (low birth weight)?

Four studies have not shown reduced growth in the womb of babies exposed in pregnancy to a quinolone antibiotic. A very small study also found no increased likelihood of a baby having a low birth weight after being exposed in the womb to oxolinic acid (a quinolone which is not available in the UK), however more research is required to confirm this finding. No studies have investigated growth in the womb in babies exposed to other specific quinolones.

Can taking a quinolone antibiotic 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.

Two studies that analysed women using a quinolone antibiotic in pregnancy as a group found that their babies reached their developmental milestones at the same time as babies not exposed to quinolones in the womb. Although this offers some reassurance, further research into other aspects of learning and development in children exposed in the womb to quinolones is 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 quinolone antibiotic 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 quinolone antibiotic?

We would not expect any increased risk to your baby if the father took a quinolone antibiotic 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.