SEARCH

SEARCH BY CITATION

Keywords:

  • antibiotics;
  • cardiovascular malformations;
  • drug safety;
  • erythromycin;
  • pregnancy outcome

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• It has generally been regarded as safe to take erythromycin during pregnancy. A recent study from Sweden found that erythromycin exposure in the first trimester was associated with congenital cardiovascular defects. The results led to warnings against using erythromycin in the first trimester from both the Swedish and Norwegian governments.

WHAT THIS STUDY ADDS

• This large, population-based register study did not find that erythromycin or macrolide use in pregnancy was significantly associated with congenital malformations, cardiovascular malformations or any other specific malformation.

AIMS Erythromycin is a macrolide antibiotic indicated for respiratory tract infections, genital chlamydia and skin infections. It has recently been suggested that erythromycin use in the first trimester of pregnancy can increase the risk of congenital cardiovascular malformations. This study aimed to determine whether erythromycin exposure in the first trimester is associated with cardiovascular or other malformations.

METHODS We studied 180 120 women in Norway who were pregnant during 2004–2007. Data on all live births stillbirths and induced abortions after 12 gestational weeks from The Medical Birth Registry of Norway (MBRN) were linked to information from the Norwegian prescription database (NorPD). We compared the pregnancy outcomes of women who had taken erythromycin (n= 1786, 1.0%), penicillin V (n= 4921, 2.7%) or amoxicillin (n= 1599, 0.9%) in their first trimester with outcomes of women who had not taken any systemic antibiotics (n= 163 653, 90.9%) during this period.

RESULTS The risk of cardiovascular malformations was not significantly different with or without exposure to erythromycin in the first trimester (adjusted OR = 1.2 [95% CI 0.8, 1.8]) or in the most vulnerable period of heart formation (adjusted OR = 1.6 [95% CI 0.9–3.0]). Sub-analyses showed that the risk for any specific malformations was not increased with erythromycin, macrolides, penicillin V or amoxicillin compared with no antibiotic use in first trimester.

CONCLUSIONS This large, population-based register study did not find that exposure to erythromycin or macrolides in the first trimester of pregnancy was associated with fetal cardiovascular or other malformations. These results suggest that the risk of erythromycin use during early pregnancy, if any, is low.