The bacteria Chlamydia trachomatis causes a common bacterial sexually transmitted infection. This infection is often described as “silent” because a majority of infected people show no immediate signs or symptoms. While easily treated with antibiotics, its asymptomatic nature means it can persist in the body for months or even years without being detected. If left untreated, the infection can progress, leading to severe and permanent complications that directly impact a person’s ability to conceive.
How Untreated Chlamydia Leads to Reproductive Damage
The silent nature of the infection allows it to cause long-term damage, as approximately 70% of women and 50% of men may experience no symptoms. The infection typically begins in the lower genital tract, such as the cervix or the urethra. If the bacteria is not eliminated, it can spread through a process known as ascending infection, moving upward into the reproductive organs.
In women, the infection can travel from the cervix to the uterus, fallopian tubes, and ovaries. The presence of the bacteria triggers a sustained inflammatory response within these tissues. This prolonged inflammation ultimately leads to the formation of scar tissue and adhesions, which are bands of fibrous tissue that cause organs to stick together, resulting in permanent tissue alteration and infertility.
Specific Infertility Risks for Women and Men
For women, the most significant complication is Pelvic Inflammatory Disease (PID), an infection of the female reproductive organs developing in about 10–15% of women with untreated Chlamydia. Inflammation and scarring within the fallopian tubes often lead to tubal factor infertility (TFI), where damaged tubes prevent the egg from traveling to the uterus for fertilization or implantation.
Scarring from PID also increases the risk of an ectopic pregnancy, where a fertilized egg implants outside the uterus, most commonly in the fallopian tube. This premature implantation is a potentially life-threatening condition. Chlamydia is a preventable cause of PID, which is responsible for a significant percentage of female infertility cases.
In men, untreated Chlamydia most commonly causes epididymitis, inflammation of the epididymis (a coiled tube that stores and carries sperm). Inflammation can cause pain, swelling, and scarring that obstructs sperm passage, leading to reduced fertility. The infection can also negatively affect sperm quality, causing DNA damage and reducing sperm motility, which impacts fertilization.
Diagnosis and Effective Treatment Protocols
Detecting Chlamydia involves highly sensitive laboratory tests that look for the bacteria’s genetic material. The most common method is a Nucleic Acid Amplification Test (NAAT), performed on a simple first-catch urine sample or a swab. For women, a swab can be taken from the cervix or vagina, and this sample can often be self-collected. Testing is necessary because the infection is frequently asymptomatic.
Once diagnosed, Chlamydia is cured with a short course of antibiotics. The standard treatment for non-pregnant adults is a seven-day course of doxycycline, taken twice daily. An alternative single-dose treatment of azithromycin may also be used when adherence to a multi-day regimen is a concern. Treatment is highly effective, being approximately 95% successful at eradicating the bacteria. Patients must abstain from sexual activity until the treatment course is complete.
Prevention Through Screening and Risk Reduction
Preventing the long-term reproductive consequences of Chlamydia requires regular screening. Public health guidelines recommend annual screening for all sexually active women aged 25 and younger, who have the highest rates of infection. Women older than 25 who have new or multiple sexual partners, or a partner with a known STI, should also be screened annually.
Risk reduction strategies prevent both infection and re-infection. Consistent use of barrier protection, such as condoms, significantly lowers the risk of transmission. Furthermore, anyone diagnosed must ensure that all sexual partners from the preceding 60 days are also tested and treated. This practice, known as partner treatment, is crucial to break the cycle of transmission and prevent reinfection.