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Prenatal screening and treatment are needed to identify pregnant women with asymptomatic chlamydial infections

Chlamydia trachomatis is the most common bacterial sexually transmitted disease in the United States, and it occurs most often among young, sexually active women. As many as 60 to 70 percent of women with Chlamydia are asymptomatic.

Nine percent of pregnant women who have Chlamydia have no symptoms associated with the infection, according to a recent study of nearly 2,000 pregnant women with Chalmydia. The study was supported in part by the Agency for Healthcare Research and Quality (contract 290-92-0055). In 44 percent of the women, the infection resolved spontaneously, but most women with asymptomatic infection who were not treated had persistent infection.

Persistent Chlamydia infection has been implicated in preterm delivery and preterm rupture of membranes. This underscores the need for prenatal chlamydial screening and treatment, according to Jeanne S. Sheffield, M.D., of the University of Texas Southwestern Medical Center, Dallas.

Currently, annual Chlamydia screening is recommended for all sexually active women aged 24 and younger and older women with risk factors. It is also recommended for pregnant women at the first prenatal visit and again in the third trimester for those with risk factors for chlamydial infection. In the current study, the researchers examined spontaneous resolution of chlamydial infection in a large multicenter trial involving 140 women who screened positive for the infection (between the 16th and 23rd week of pregnancy) but had no symptoms of infection (9 percent).

Forty-four percent of the women had spontaneous resolution of chlamydial infection by the followup assay (between the 24th and 29th weeks of pregnancy). For every 5-year increase in maternal age, the odds of a positive result (lingering infection) on the followup assay decreased by 40 percent. A longer period (more than 5 weeks) from initial study enrollment to followup screening was also associated with spontaneous resolution. This is consistent with the theory that the immune system has a better chance of eliminating infections over time.

See "Spontaneous resolution of asymptomatic Chlamydia trachomatis in pregnancy," by Dr. Sheffield, Williams W. Andrews, Ph.D., M.D., Mark A. Klebanoff, M.D., and others, in the March 2005 Obstetrics & Gynecology 105, pp. 557-562.

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