Chlamydia trachomatis is a bacterium that causes one of the most common sexually transmitted infections (STIs) globally, affecting millions of people each year. The infection is often called a “silent” infection because a majority of those infected, particularly men, experience no noticeable symptoms, making diagnosis and treatment challenging. This asymptomatic nature allows the bacteria to persist in the body, potentially leading to serious complications if left untreated. This article examines the specific risk that this common, often undetected, infection poses to male fertility.
The Link Between Chlamydia and Male Infertility
The direct answer to whether Chlamydia can cause male infertility is yes, it can contribute to it. Studies have consistently found a higher prevalence of C. trachomatis in the semen and reproductive tracts of men experiencing infertility compared to fertile men. One meta-analysis estimated that infection with C. trachomatis is associated with a significantly higher risk of male infertility.
The prevalence of C. trachomatis infection in infertile men has been estimated to be around 20.6% in some studies, underscoring the correlation between the pathogen and fertility issues. While a significant proportion of men who contract the infection will not become infertile, the risk is substantial enough to warrant public health attention and routine testing.
The evidence suggests that C. trachomatis may be an underestimated factor in cases of male infertility where the cause is otherwise unknown. Its role in male factor infertility is increasingly recognized, even though its impact is less pronounced than its effects on female fertility. Recognizing this established link is the first step toward effective screening and preventative measures.
Biological Mechanisms Causing Damage
The damage to male fertility caused by C. trachomatis occurs through a combination of inflammatory responses and direct action within the reproductive tract. The ascending infection often travels from the urethra to the epididymis, the coiled tube behind the testicle where sperm mature and are stored. Inflammation of this structure, known as epididymitis, is a common complication of untreated Chlamydia.
Chronic or severe inflammation in the epididymis can lead to the formation of scar tissue, which can obstruct the delicate tubules within the epididymis or the vas deferens, the duct that transports sperm. This physical blockage prevents the passage of sperm into the ejaculate, a condition known as obstructive azoospermia. The infection can also spread to the prostate (prostatitis) or the testicles (orchitis), further compromising the reproductive system.
Beyond structural damage, the infection can directly affect sperm quality and function. The presence of the bacteria or the immune response it triggers can lead to increased oxidative stress within the semen. This stress damages sperm membranes and causes fragmentation of sperm DNA, which is linked to poor reproductive outcomes. Research has shown that infected sperm exhibit decreased motility, a higher number of non-viable forms, and impaired morphology.
Screening, Treatment, and Prevention
Given the high rate of asymptomatic infection, routine screening is a strategy for preventing the long-term reproductive complications of C. trachomatis. Screening is performed using a nucleic acid amplification test (NAAT), which detects the bacteria in a first-catch urine sample or a swab from the urethra. While routine screening for all sexually active men is not universally recommended, it is advised for those considered at higher risk, such as men with new or multiple sexual partners.
Once diagnosed, Chlamydia is a curable bacterial infection that is treated effectively with antibiotics. The standard treatment regimens involve a short course of oral antibiotics, such as a single dose of azithromycin or a seven-day course of doxycycline. Completing the entire course of medication is necessary to ensure the infection is fully cleared and to prevent antibiotic resistance.
A primary component of treatment is ensuring that all recent sexual partners are also tested and treated to prevent reinfection and onward transmission. Individuals should abstain from sexual contact for seven days after completing a single-dose regimen or until the completion of the full seven-day course. Prevention relies on safer sexual practices, including the consistent and correct use of barrier methods like condoms, which significantly reduce the risk of transmission.