Peter S. Bernstein, MD, MPH, FACOG; Lev D. Kandinov, MD


August 27, 2004


I have a 29-year-old patient with a pregnancy stopped in evolution in March of this year. She is pregnant again -- 6 weeks -- and the results of her serology for Chlamydia were inconclusive for IgA. Except for repeating the test, what can you tell me about the effects of Chlamydia on the pregnancy, especially in the first term? Could it affect the development of the placenta or of the fetus?

Response from Peter S. Bernstein, MD, MPH, FACOG and Lev D. Kandinov, MD

Lev D. Kandinov, MD
Chief Resident, Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York

Peter S. Bernstein, MD, MPH
Associate Professor of Clinical Obstetrics & Gynecology and Women's Health, Division of Maternal-Fetal Medicine, Dept. of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York

Chlamydia trachomatis (CT) is the most common sexually transmitted pathogen in the United States and the Western world. Approximately 3 million cases are diagnosed annually in the United States at a cost of greater than 2 billion dollars. Patients at risk are usually young (15 to early 20s), nonwhite, single, have multiple sexual partners, and use nonbarrier contraception methods.

CT is an obligate intracellular parasite. Fifteen serotypes exist; serotypes D, E, F, G, H, I, J, and K are responsible for genital tract and perinatal infections.

CT preferentially infects the columnar epithelium of the upper and lower genital tract, urethra, and anus. Although in many patients CT infection is "silent," common clinical manifestations include cervicitis, urethritis, vaginitis, and pelvic inflammatory disease (PID). Untreated infection can spread into the uterus or fallopian tubes and cause PID. This happens in up to 40% of women with untreated CT. PID can cause permanent damage to the fallopian tubes, uterus, and surrounding tissues, which can lead to chronic pelvic pain, infertility, and ectopic pregnancy.[1,2]

Centers for Disease Control and Prevention recommendations for testing include: (1) annual screening for CT for all sexually active women aged 25 years and younger; (2) older women with risk factors for CT (a new sex partner or multiple sex partners); and (3) all pregnant women should have a screening test for CT.[2]

In pregnant women, CT infections can lead to ectopic pregnancy, preterm premature rupture of membranes (PPROM), and premature delivery. It is classically believed that in pregnant patients, cervical mucus and pregnancy itself prevent spread of infection from lower genital tract to the uterus and fallopian tubes. Nevertheless, some case reports and serologic work suggest that CT can possibly infect the placenta and thus harm the fetus. This, however, remains controversial. Whereas some studies found no correlation between CT infection and spontaneous abortion, others have found an increased risk of spontaneous first trimester abortion in patients infected with CT. Although the mechanism of pregnancy loss secondary to CT infection is unclear, 2 models are proposed for the pathogenesis of CT-related early abortions: (1) direct zygote infection, and (2) immune response to heat shock proteins expressed by the zygote and triggered by previous CT infections.[3,4]

In patients with PPROM, CT infection interferes with collagen maintenance and degradation.[5]

There is no reported evidence that CT causes direct harm to the development of the fetus. Infants who are born to infected mothers are at risk for chlamydial conjunctivitis and pneumonia. In fact, CT is a leading cause of early infant pneumonia and conjunctivitis in newborns.[1,5]

In conclusion, the recommendations are to test every pregnant patient at the first prenatal visit using DNA probe. Tetracycline and doxycycline show the greatest activity against CT; however, these agents are contraindicated in pregnancy. Thus, patients who test positive should be treated with azithromycin 1 g orally in a single dose. There is 5% to 10% failure rate to initial treatment; therefore, a test of cure should be done 2 to 3 weeks after the initial treatment. These patients should also be screened for other sexually transmitted infections. In addition, the patient's partner should always be treated as well.[1,2,5]


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