Islamabad - Women who take certain types of antibiotics during early pregnancy may be at an increased risk of miscarriage, a new study suggests.

But not all antibiotics are alike, and some antibiotics may be safer during pregnancy than others.

Researchers in Canada found that mothers-to-be who used certain classes of antibiotics had a small increase in risk of miscarriage before the 20th week of pregnancy compared with pregnant women who did not take any antibiotics, according to the study.

“The study found that the most frequently used antibiotics - penicillin, cephalosporin and erythromycin - are not associated with an increased risk of miscarriage,” said lead study author Anick B#rard, a pharmacy professor at the University of Montreal in Canada.

Despite the frequent use of antibiotics during pregnancy to treat a variety of infections, the safety of exposing the foetus to these medications remains a concern, the study authors wrote.

The researchers compared the cases of the more than 8,700 women who had suffered a miscarriage during their first 20 weeks of pregnancy to about 87,000 women who did not. Among these women, who ranged in age from 15 to 45, about 12,500 had taken an antibiotic during pregnancy.

The study found that five broad classes of antibiotics - macrolides, quinolones, tetracyclines, sulfonamides and metronidazole - were linked with an increased risk of miscarriage during early pregnancy. They noted that one macrolide, erythromycin, was not linked with an increased risk of miscarriage.