Pregnant women have been warned that a type of antibiotic could harm their unborn baby . Researchers from Great Ormond Street Hospital and University College London have linked erythromycin pills with epilepsy and cerebral palsy . The study tracked the health of babies born to 200,000 British women . Overall , the babies born to women who took antibiotics were no more likely to develop epilepsy or cerebral palsy . Woman have been warned the common antibiotic erythromycin could harm their unborn baby ( file photo ) But women treated with erythromycin and other pills from the macrolide family of antibiotics were almost twice as likely to have a baby with one of these conditions as those given penicillin . The study , published in the journal PLOS ONE , found that a third of expectant mothers were given antibiotics during pregnancy , most commonly penicillin . Just 7 per cent of the women prescribed antibiotics were given macrolides , which are used to treat urinary and chest infections and are particularly likely to be given during recurrent illness or if a woman is allergic to penicillin . However out of every 150 women given a macrolide rather than penicillin , there was one more baby born with cerebral palsy or epilepsy . Researcher Professor Ruth Gilbert advised pregnant women to keep taking any antibiotics that they are prescribed – as an infection is likely to harm their baby . Erythromycin are from the macrolide family of antibiotics . Macrolides are used to treat urinary and chest infections and are particularly likely to be given during recurrent illness or if a woman is allergic to penicillin . And she stressed that any increased risk to the unborn child posed by the pills would be extremely small . However , with four previous studies raising concerns about the pills , she said it was time for the pills to be thoroughly reviewed by the Medicines and Healthcare Products Regulatory Agency ( MHRA ) . Professor Andrew Whitelaw , of Bristol University , warned that a bad infection could end up killing both the mother and her child . But he added : ‘ Nevertheless , drug treatment in pregnancy requires a very high level of safety and it will not surprise me if the regulatory authorities advise doctors to avoid or severely restrict macrolides in pregnancy ’ . Others said that the study does not prove that macrolides are harmful , as it could be that the bugs they are used treat are more likely to damage the brain than other infections . Erythromycin is used to treat urinary and chest infections and are particularly likely to be given during recurrent illness or if a woman is allergic to penicillin . Dr Christoph Lees , of Imperial College London , said : ‘ One thing is for sure : pregnant women should definitely take antibiotics when prescribed them as the risk of untreated infection to the pregnancy can be catastrophic . ‘ To put things in context , the extra risk to their baby of being prescribed macrolides , if indeed there is a risk , is very tiny. ’ The medicines ’ watchdog , the MHRA , said it has already sought independent advice on the study and it does not consider that the research provides proper proof that macrolides are dangerous . A spokesman said : ‘ Importantly , this study found no overall evidence of harm when antibiotics are prescribed in pregnancy . ‘ Any pregnant woman who has been prescribed antibiotics should continue to take them as instructed and speak to their healthcare professional if they have any questions . ’
Erythromycin is an antibiotic given for urinary and chest infections . Is prescribed during recurrent illness or for people allergic to penicillin . Researchers called for a safety review but stressed increased risk is small . Overall , study found antibiotics taken during pregnancy were safe .