Does Antibiotic Exposure Lead to Miscarriage Risk?

New research published in the Canadian Medical Association Journal suggests that some commonly prescribed antibiotics may be linked to higher risk of miscarriage in early pregnancy.

Researchers examined data from the Quebec Pregnancy Cohort between 1998 and 2009 to evaluate antibiotics’ association with increased miscarriage risk. In the study, 8702 instances of clinically detected spontaneous abortions, were randomly matched with 10 controls per case by gestational age and year of pregnancy. Use of antibiotics was defined by filled prescriptions between the first day of gestation and the index date, and was compared with non-exposure and exposure to penicillins or cephalosporins.

Participants included women between the ages of 15 and 45 years old who were covered under Quebec’s drug insurance plan. Researchers excluded planned abortions and pregnancies exposed to fetotoxic drugs. Type of antibiotics was studied separately using comparator groups.

The results revealed that exposure to macrolides (excluding erythromycin), quinolones, tetracyclines, sulfonamides, and metronidazoles during early pregnancy was linked to an increased risk of spontaneous abortion. The findings also indicated that women who miscarried were more likely to be older, living alone, and to have multiple health issues and infections.

Although the study exhibited strengths in its sample size and valid, routinely collected information on spontaneous abortions or related procedures, the researchers noted that infection severity could be a confounder to miscarriage and explain some of the increased risk. However, the researchers did adjust for this potential variable in their analysis.

The researchers concluded that the findings could be useful in guideline considerations for treating infections during pregnancy.

Reference

Muanda FT, Sheehy O, Berard A. Use of antibiotics during pregnancy and risk of spontaneous abortion. CMAJ. May 1, 2017; 189(17); doi:10.1503/cmaj.161020.