Chlamydia during pregnancy

By trimester

Weeks 1–13

1st trimester

CDC recommends screening at the first prenatal visit for every pregnant person younger than 25 and for older patients with increased risk. A urine sample or vaginal swab can detect infection even when discharge or burning is absent.

Weeks 14–27

2nd trimester

During pregnancy, CDC lists a single azithromycin dose as the preferred regimen and amoxicillin for seven days as an alternative. The exact prescription belongs with a clinician, followed by a nucleic acid test to confirm clearance about four weeks after completion.

Weeks 28–birth

3rd trimester

Pregnant patients who remain at increased risk should be screened again in the third trimester. Anyone with chlamydia also needs repeat testing three months after the antibiotic course, and partner care matters because most later positive results reflect reinfection rather than antibiotic failure.

What does the evidence show for chlamydia?

• CDC's pregnancy regimen is azithromycin 1 gram by mouth once, with amoxicillin 500 milligrams by mouth three times daily for seven days as an alternative; doxycycline is contraindicated in the second and third trimesters. 1
• Pregnancy follow-up includes a nucleic acid test to confirm clearance about four weeks after the antibiotic course and repeat testing three months later; testing sooner than four weeks can detect nonviable organisms and yield a misleading positive result. 1
• CDC recommends first-visit screening for pregnant patients younger than 25 and for older patients with increased risk, plus third-trimester rescreening when risk continues. 2
• Chlamydia is frequently asymptomatic, can cause discharge or burning with urination, and can pass to a newborn during birth; laboratory testing rather than symptoms establishes infection. 3
• WHO also favors azithromycin over erythromycin in pregnancy, but its comparison with amoxicillin rests on low-quality evidence with wide confidence intervals, so the current US CDC regimen should guide US care. 4

When should I call my provider about chlamydia?

Contact your pregnancy clinician promptly for fever, worsening lower abdominal or pelvic pain, pain with sex, unusual discharge, burning with urination, or unexpected vaginal bleeding. Suspected pelvic inflammatory disease during pregnancy warrants hospital-based evaluation. Seek urgent care for severe belly pain that does not go away, fainting, heavy vaginal bleeding, or inability to keep fluids down rather than waiting for the scheduled four-week follow-up. When in doubt, call your obstetric team the same day. Early input almost always beats waiting, and the on-call line exists exactly for this.