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Chlamydia Infection in Pregnancy

What Do I Have?

Chlamydia is an infection caused by the Chlamydia trachomatis bacterium and is spread from person-to-person through direct sexual contact. It is the most common of all bacterial sexually transmitted diseases (STDs) in the and is particularly prevalent among young women.

In women, chlamydia infection primarily affects the uterine cervix (the narrow end of the uterus). However, chlamydia has also been found in the urethra, rectum, uterus, fallopian tubes, and the glands near the opening of the vagina. In some non-pregnant women, untreated chlamydial infections can lead to life-threatening complications, such as pelvic inflammatory disease and pelvic abscess. A pregnant woman with chlamydia during labor and delivery may pass the infection to her baby, which may cause serious eye or lung infections.

Although chlamydia can cause other STDs and systemic illnesses in men and women, this review focuses primarily on diseases of the female genital tract and congenital infections in infants.

About Chlamydia Trachomatis:

Chlamydia trachomatis an unusual bacterium in that it can survive and reproduce only inside the cells of a host organism. During its life cycle, it has two forms: the elementary body and the reticulate body. The elementary body is the form that infects cells lining the eye surface or the genitourinary, gastrointestinal, or respiratory tracts. It attaches to the cell surface and is engulfed into an intracellular compartment known as a phagosome, where it is transformed into the metabolically active reticulate body. Using the host's energy supply, the reticulate body undergoes many rounds of cellular division to produce 100 to 500 offspring within the phagosome. The reticulate bodies mature into elementary bodies that are released from the host cell to infect other cells.

How Common Are Chlamydial Infections in the U.S.?

Approximately 500,000 chlamydial infections are reported to the Centers for Disease Control and Prevention (CDC) each year. However, the actual annual incidence is estimated to be 10 to 20 times that figure. Determining the extent of chlamydial infection is difficult. For one thing, some states are more accurate than others in compiling and reporting data on known cases of chlamydia to the CDC. Also, this infection may not cause symptoms; therefore, large-scale screening programs are needed to identify people with asymptomatic chlamydia. Resources for such programs are limited. Even if such programs existed, many infected persons would not report for screening. But, even with so many hidden cases of this infection, chlamydia costs the over $2.4 billion in direct and indirect costs each year.

Are Some People More Susceptible to Chlamydia?

Chlamydia is particularly prevalent in adolescents and young adults, with the highest rates of infection occurring in 15- to 24-year-old women. Women who are poor, of minority race, unmarried, live in a large city, and who became sexually active at an early age are at high risk of infection. Other risk factors include multiple sex partners, exposure to a partner who has had multiple sex partners, and illicit drug use.

Among men, infection is most common among the same age groups, but reported rates are lower overall (0.6% of the male population, compared to 3.0% of women). Though seemingly reassuring, the lower rates in men suggest that many of the sex partners of women with chlamydia are not being diagnosed or reported. Compared to asymptomatic women, asymptomatic men are less apt to receive medical attention.

What Are the Symptoms and Complications of Chlamydia?

Most women with chlamydia do not have symptoms. Some infected women, however, do develop a yellowish discharge of mucus and pus from the cervix or vagina, abdominal pain, or bleeding between menstrual periods. Those with chlamydial infection of the urethra (the canal through which urine is eliminated) frequently have symptoms that mimic a bladder infection, such as the frequent need to urinate, a burning sensation during urination, and pain during intercourse.

Because so many women with chlamydia are without symptoms, infections often go untreated. As a result, the infection can ascend from the lower to the upper genital tract, leading to more serious conditions. These may include endometritis (infection of the internal lining of the uterus) and salpingitis (infection of the fallopian tubes, also known as pelvic inflammatory disease, or PID). These conditions may, in turn, lead to serious complications.

  • Endometritis can cause infection of pelvic blood vessels and bloodstream (bacteremia) and septic shock, which is potentially fatal.
  • Salpingitis may lead to permanent infertility, ectopic (tubal) pregnancy, and chronic pelvic pain.

Unfortunately, upper genital tract infections due to chlamydia may or may not cause symptoms. This increases a woman's vulnerability to long-term complications.

What Are the Implications of Chlamydial Infection During Pregnancy?

Chlamydial infection during pregnancy poses a unique challenge. As in non-pregnant women, most pregnant women with chlamydial infection are without symptoms, so the infection can easily go undetected. However, many uninfected women who are pregnant develop a mucus discharge similar to the discharge that occurs in chlamydia cervicitis (inflammation of the cervix). This adds to the difficulty of diagnosing chlamydia accurately.

Pregnant women have a degree of protection against some of the potential complications of chlamydia. For instance, the fetal membranes can help prevent the infection from ascending into the uterus or fallopian tubes. Yet, other complications of chlamydia are specific to pregnancy.

Of serious concern is the risk of the infection being transmitted from a mother to her baby during vaginal delivery. When this occurs, it is presumably because the baby comes into contact with the mother's genital secretions. As a result, the baby may develop an eye infection (conjunctivitis ) or lung infection (pneumonia ). Conjunctivitis caused by chlamydia is one of the most common causes of preventable blindness worldwide, although it is rare in the since newborns are routinely given erythromycin ophthalmic ointment to prevent eye infections. Nonetheless, this method is less effective in preventing chlamydial eye infection than in protecting against conjunctivitis caused by gonorrhea.

Screening, Treatment, and Prevention

Because chlamydia infection can cause serious problems, early diagnosis and prompt treatment are essential. Fortunately, oral antibiotic therapy cures chlamydial infection in virtually all cases and is key in preventing potential complications.

The most effective means of preventing chlamydial infection in newborns is to screen and treat pregnant women before labor. The CDC recommends that pregnant women who are less than 25 years of age or who have new or multiple sex partners be tested for chlamydia. The sexual partners of infected women should also be tested and, if appropriate, treated to prevent further spread of the disease.

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