Chlamydia: From Whom, How Long Ago, and What About My Fertility?

Given that Chlamydia is the most common of the reportable sexually transmitted infection/sexually transmitted disease (STI or STD) we get many questions here at WebMD from very worried women. The most concerned questions tend to be focused on how/when the infection was acquired, and what impact will it have on future fertility. The following is a summary of the answers to those questions, and some related issues as well.

Who Gave Me Chlamydia?

If you are a sexually active woman aged twenty five years or less--and especially if you are aged less than twenty--you are a part of the largest Chlamydia infection demographic. If you are a female performing receptive oral, anal, or vaginal sex you can get Chlamydia, if secretion contact is present. Thus you need to be honest with your GYN about your sexual practices so you can be screened for possible Chlamydia infections of the pharynx, rectum, or vagina/cervix. Chlamydia can be passed between both heterosexual, and same sex couples-although its incidence is less than 1% in women who are exclusively lesbian.

How Long Ago Did I Get Chlamydia?

The incubation of a Chlamydia infection is reported to be one to three weeks. It can take up to six weeks in some cases. From one perspective it would be great if one could count back a few weeks to find the culprit-partner. But that would require that tell-tale symptoms be present. Alas, up to 75% of women and perhaps 50% of men have no symptoms. This can make it difficult to establish blame for the infection. It also means that infected persons can unknowingly continue to spread Chlamydia for a long time.

Many family planning programs do universal screening for Chlamydia among women aged twenty five or less--or if there is a new sexual partner. Certainly if a woman comes in with symptoms of vaginal discharge, the GYN or clinic would be likely to test for STDs, as well as for other vaginal infections. There is often screening during the initial prenatal visits in an attempt to prevent the infant from becoming infected during delivery with Chlamydial infections of the eyes or lungs.

Other instances when a woman might be tested for Chlamydia would be if she presents for an infertility work up, or with pain from a pelvic infection. These two conditions are linked. If Chlamydia ascends up through the cervix to infect the uterus/tubes/ovaries a woman can develop "Pelvic Inflammatory Disease" ("PID"). Some symptoms of PID include: lower abdominal pain, pain with sex, breakthrough bleeding, fever, or even nausea.

Studies have shown that between 20-40% of women with untreated Chlamydia will go on to develop scarring inside the Fallopian tubes, or bands of scar tissue ("adhesions") inside the pelvis. Inflammation from the untreated infection creates this scarring. This impacts fertility by blocking the tubes so fertilization cannot occur, and by "webbing" the open end of the Fallopian tubes to impair egg "capture" at ovulation. One author (Mardah, 2004 ) posits that the "The tubal infection may become chronic in spite of antibiotic therapy." This would infer that even after treatment a percentage of women may have tubal damage.

How Will Chlamydia Affect MY Fertility?

It has been calculated that perhaps 1,000,000 women per year will get PID of some type. Of those, an estimated 10% will develop infertility. One landmark study (Westrom, 1996) followed almost 1,500 women, of whom about 2/3 had confirmed PID as documented by a laproscope. Among the women with a PID history 7.8% had tubal occlusion where the tube was scarred closed. By contrast, a comparison group without PID had less than 1% tubal occlusions.

In this same study it was determined that the risk of PID caused infertility was tied to:

The number of times a woman had PID:
Zero episodes---1%
Two episodes---11.3%
Three episodes--19.8%

The severity of the infection influenced the relative risk (RR) of tubal infertility:

Mild infection-------- RR 1.0
Moderate infection---RR 1.8
Severe infection------RR 5.6

PID can be caused by other organisms (eg gonorrhea, anaerobic bacteria), thus this study attempted to identify the risk of tubal damage from having only Chlamydia :

Nonchlamydial--------RR 1.0
Chlamydia-------------RR 1.7

From this data it can be inferred that the greatest impact of Chlamydia on fertility would arise if a woman had a severe PID and/or repeated infections.

Could I have had a false positive Chlamydia test?

There are a variety of tests for Chlamydia; each has its own specificity and sensitivity which means that each has a different risk of false results. There are three basic types: culture, immunoassay, and nucleic acid amplification (NAAT). For a clear explanation of each, click here.

To summarize the scientific studies comparing the reliability of the various tests, the culture and immunoassay types are between 10-30% less sensitive than the nucleic acid amplification tests (Gaydos, 2004). A few of the immunoassay tests will cross react with the subtypes of Chlamydia which are not implicated in GYN infections. Some labs will do a confirmatory test if the screening test is positive--especially if a non-NAAT variety. It is important to note that false negative tests can occur as well.

 Thus if Chlamydia is suspected a clinician will often "treat first; ask questions later." Given the lack of symptoms in many Chlamydia infections this may be the best way to prevent its GYN outcomes.

Related Topics:

• Chlamydia, STD Rates Soar in US
• Learn about STD Testing

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