What is the appropriate treatment for genital Chlamydia trachomatis infection in a patient who is 26 weeks pregnant?

Treatment for Chlamydia at 26 Weeks Pregnancy

Azithromycin 1 g orally as a single dose is the first-line treatment for chlamydia at 26 weeks of pregnancy, with a cure rate of 94-100% and excellent compliance. 1, 2, 3

First-Line Treatment

• Azithromycin 1 g orally in a single dose is the preferred regimen recommended by the American College of Obstetricians and Gynecologists and the Centers for Disease Control and Prevention for pregnant women at any gestational age, including 26 weeks. 1, 2, 3

• This regimen achieves cure rates of 94-100% in pregnancy, significantly superior to alternative options. 3, 4

• Azithromycin is FDA Pregnancy Category B with extensive clinical experience supporting its safety throughout all trimesters, including the first trimester. 3

• The single-dose regimen ensures directly observed therapy and eliminates compliance concerns, which is particularly important in pregnancy. 1

Alternative Treatment Option

• Amoxicillin 500 mg orally three times daily for 7 days is the only acceptable alternative if azithromycin cannot be used. 1, 2

• Amoxicillin demonstrates comparable efficacy to azithromycin (58% vs 64%, not statistically different) with fewer gastrointestinal side effects than erythromycin-based regimens. 2, 5

Erythromycin Regimens (Use Only When Necessary)

If both azithromycin and amoxicillin are contraindicated or unavailable, erythromycin-based regimens may be used, but they have significantly lower efficacy:

• Erythromycin base 500 mg orally four times daily for 7 days has only 64-77% efficacy compared to 94-100% for azithromycin. 2, 3

• Alternative erythromycin dosing includes erythromycin base 250 mg orally four times daily for 14 days, erythromycin ethylsuccinate 800 mg orally four times daily for 7 days, or erythromycin ethylsuccinate 400 mg orally four times daily for 14 days. 1, 2

• Erythromycin causes frequent and severe gastrointestinal side effects that reduce patient compliance. 2, 3

Absolute Contraindications in Pregnancy

• Doxycycline is absolutely contraindicated during pregnancy due to teratogenic risk. 1, 2, 3

• All fluoroquinolones (ofloxacin, levofloxacin) are absolutely contraindicated in pregnancy. 1, 2, 3

• Erythromycin estolate is absolutely contraindicated due to drug-related hepatotoxicity in pregnancy. 1, 2, 3

Mandatory Follow-Up Testing

• Test-of-cure is mandatory in all pregnant women 3 weeks after completion of therapy, unlike non-pregnant patients where it is not routinely recommended. 1, 2, 3

• This requirement exists because alternative regimens have lower efficacy, and untreated infection has serious maternal and neonatal consequences. 2, 3

• Culture is the preferred method for test-of-cure when available; if nucleic acid amplification tests are used, testing must be delayed at least 3-4 weeks to avoid false-positive results from residual DNA. 1

• Recent data show that 14% of pregnant women have persistent infection and an additional 9% have recurrence after azithromycin treatment, emphasizing the importance of test-of-cure. 6

Partner Management

• All sexual partners from the previous 60 days must be evaluated, tested, and empirically treated with the same chlamydia-effective regimen, even if asymptomatic. 1, 2, 3

• The patient must abstain from sexual intercourse for 7 days after initiating treatment and until all partners have completed treatment to prevent reinfection. 1, 2, 3

• Concomitant gonorrhea or syphilis in pregnancy is independently associated with persistent or recurrent chlamydia (adjusted odds ratio 1.6,95% CI 1.1-2.4), requiring concurrent treatment. 6

Neonatal Consequences of Untreated Infection

• Untreated maternal chlamydia leads to perinatal transmission resulting in neonatal conjunctivitis (5-12 days after birth) and subacute pneumonia (1-3 months of age). 2, 3

• Neonatal ocular prophylaxis with silver nitrate or antibiotic ointments does not prevent chlamydial transmission but should be continued to prevent gonococcal ophthalmia. 2

Common Pitfalls to Avoid

• Do not use doxycycline, fluoroquinolones, or erythromycin estolate in pregnancy—these are absolutely contraindicated. 1, 2, 3

• Do not omit the test-of-cure—it is mandatory in pregnancy due to lower efficacy of alternative regimens and serious consequences of persistent infection. 2, 3

• Do not confuse azithromycin with clarithromycin, which is teratogenic in animals and should be avoided. 3

• Do not assume partners were treated—directly verify or use expedited partner therapy strategies, as nearly 1 in 4 pregnancies have persistent or recurrent chlamydia after treatment. 6

• Ensure partner treatment is documented, as failing to treat sex partners leads to reinfection in up to 20% of cases. 1