An observational cohort study of Chlamydia trachomatis treatment in pregnancy

Sex Transm Dis. 2006 Feb;33(2):106-10. doi: 10.1097/01.olq.0000187226.32145.ea.


Background and objectives: Currently, azithromycin is not considered a first-line treatment for Chlamydia trachomatis in pregnant women. We evaluated the use, efficacy, and safety of azithromycin compared with erythromycin and amoxicillin in the treatment of genital chlamydial infection during pregnancy.

Methods: This was a retrospective cohort study of pregnant women with genital chlamydial infection. Data on antibiotics prescribed, test-of-cure (TOC) results, and maternal and infant complications were collected from medical records.

Results: Of the 277 women in the study sample, 69% were initially prescribed azithromycin, 9% amoxicillin, and 19% erythromycin. Eight-one percent of subjects had a TOC 7 or more days after diagnosis and before delivery. Treatment efficacy, as defined by a negative TOC, was 97% (95% confidence interval [CI], 92.9-99.2) for azithromycin, 95% (95% CI, 76.2-99.9) for amoxicillin, and 64% (95% CI, 44.1-81.4) for erythromycin. The efficacy of azithromycin was significantly higher than erythromycin (P < 0.0001). There were no significant differences in efficacy by age, race/ethnicity, concurrent sexually transmitted disease diagnosis, partner treatment, or substance use. Furthermore, there was no difference in complications for women or infants exposed to azithromycin compared with those treated with other regimens.

Conclusion: Clinical outcome data from this study population of women and infants support both efficacy and safety of azithromycin for treatment of C. trachomatis in pregnancy.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amoxicillin / therapeutic use
  • Anti-Bacterial Agents / therapeutic use*
  • Azithromycin / therapeutic use
  • Chlamydia Infections / drug therapy*
  • Chlamydia Infections / microbiology
  • Chlamydia trachomatis* / drug effects
  • Cohort Studies
  • Erythromycin / therapeutic use
  • Female
  • Genital Diseases, Female / drug therapy*
  • Genital Diseases, Female / microbiology
  • Humans
  • Infant, Newborn
  • Pregnancy
  • Pregnancy Complications, Infectious / drug therapy*
  • Pregnancy Complications, Infectious / microbiology
  • Pregnancy Outcome
  • Retrospective Studies
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Erythromycin
  • Amoxicillin
  • Azithromycin