A prospective controlled multicentre study of clarithromycin in pregnancy

Area of Science:

• Pharmacology
• Obstetrics
• Teratology

Background:

• Clarithromycin is a macrolide antibiotic used for respiratory and skin infections.
• Limited data exists on its safety during pregnancy, with animal studies showing potential risks.
• Existing human data is insufficient for evidence-based counseling of pregnant women exposed to clarithromycin.

Purpose of the Study:

• To evaluate the safety of clarithromycin use during pregnancy.
• To assess the risk of major and minor malformations in infants exposed to clarithromycin in utero.
• To investigate the rate of spontaneous abortions following first-trimester exposure to clarithromycin.

Main Methods:

• A prospective controlled study involving 157 pregnant women exposed to clarithromycin and a control group exposed to other antibiotics.
• Participants were matched for age, smoking, and alcohol use.
• Follow-up included assessment of major and minor malformations and spontaneous abortion rates.

Main Results:

• No significant differences were observed in the rates of major malformations (2.3% vs. 1.4%) or minor malformations (5.4% vs. 4.9%) between the clarithromycin-exposed and control groups.
• The spontaneous abortion rate was significantly higher in the clarithromycin-exposed group (14%) compared to the control group (7%).

Conclusions:

• Clarithromycin use in early pregnancy does not appear to increase the risk of major malformations beyond the baseline rate.
• The observed higher rate of spontaneous abortions in the clarithromycin-exposed group warrants further research.
• This study provides initial evidence for counseling pregnant women regarding clarithromycin exposure.