Drug to prevent early labor raises risk: study

LONDON (Reuters) – A drug prescribed to pregnant women to
reduce the risk of early labor could be doing patients more
harm than good, a British charity said on Friday.

Tommy’s, a charity that funds national research programs to
prevent miscarriage and stillbirths, said the antibiotic
metronidazole may double the risk of pre-term deliveries.

“Clinicians and high-risk pregnant women should be aware of
this research outcome so that we can avoid escalation of
pre-term birth and in turn, save more babies’ lives,” said
Professor Andrew Shennan, of St Thomas’ Hospital London and
professor of obstetrics for the charity.

An estimated one in 200 pregnant women in Britain are given
the drug to treat an infection called bacterial vaginosis that
can cause early labor and pre-term delivery.

Women are screened for the infection in the later stages of
pregnancy.

In a study published in BJOG: An International Journal of
Obstetrics and Gynaecology, Shennan and his colleagues studied
900 pregnant women who had a high risk of early labor. The
women were randomly divided to receive the drug or a placebo.

The scientists said 39 percent of women in the placebo
group had a pre-term delivery compared to 62 percent of women
who had received metronidazole.

“Preterm delivery may be increased by metronidazole
therapy,” Shennan said in the report.

He added that there are some serious conditions for which
the drug, a common antibiotic that has been used for decades,
is given but it should not be recommended to prevent early
labor and pre-term delivery.

“There are other antibiotics which could treat the
condition effectively,” Shennan added.