Report raises fears over premature birth drug

A drug, which is widely prescribed to pregnant women at risk of premature birth may actually do more harm than good, a report has suggested.

The study, conducted by baby charity Tommy's, found that the antibiotic metronidazole, which is given to around 1 in 20 pregnant women, doubled the risk of pre-term delivery.

The report, published in the latest edition of the International Journal of Obstetrics and Gynaecology, said that this meant 1000 babies were born prematurely each year in the UK because of exposure to the drug.

The findings came from Tommy's PREMET trial, in which 900 pregnant women between 23 and 24 weeks of pregnancy were studied.

The women identified as most at risk of premature birth were divided into two equal groups, with one group receiving one week's course of metronidazole and the other being given a placebo.

Tommy's said that the results showed that metronidazole was not only ineffective in preventing pre-term births, but could also potentially be detrimental.

Only 39% of the women in the placebo group had premature births, compared to 62% of women who took metronidazole.

The researchers said that it was thought that metronidazole might be leading to a greater incidence of premature delivery among high-risk women.

The antibiotic is usually prescribed for treatment of bacterial vaginosis, an infection, which has been associated with premature delivery.

Around 5% of the antenatal population are screened for the condition, with one in ten tests being positive, Tommy's said.

The charity said that this meant that one in 200 pregnant women were considered high-risk for delivering a premature baby as well as BV positive. They would then likely receive prescriptions for metronidazole and 30% of them would go on to deliver a premature baby.

Given that there are around 700,000 births in the UK each year, Tommy's estimates that around 1000 babies may be being born prematurely each year because of the adverse effect of the drug.

The report's author, Andrew Shennan, Professor of Obstetrics for Tommy's, said: "Clinicians and high-risk pregnant women should be aware of this research outcome, so that we can avoid the escalation of premature birth and, in turn, save more babies lives."

However, Dr Jim Kennedy, prescribing spokesperson for the Royal College of GPs said that metronidazole also reduced the risk of infection and said that the potential benefits should be weighed against the disadvantages of the drug.

(KMcA/GB)