How does chlamydia affect fertility?
Chlamydia trachomatis can travel from the cervix upwards through the uterus and into the fallopian tubes, causing inflammation known as pelvic inflammatory disease (PID). Even a single episode of PID can cause scarring in the fallopian tubes that increases the risk of infertility and ectopic pregnancy. The complication is more likely when infections go untreated — which is common, given that 70–80% of women with chlamydia have no symptoms.
What are the statistics?
Approximately 10–15% of women with untreated chlamydia will develop PID. Of those, around 20% will experience infertility as a result. The risk rises substantially with repeated or prolonged infections. Chlamydia can also cause epididymo-orchitis in men (inflammation of the epididymis and testicles), which can in rare cases affect male fertility. Early treatment with antibiotics eliminates the bacteria and, if given before PID develops, prevents these complications entirely.
Treatment
Chlamydia is treated with antibiotics — typically a single dose of azithromycin (1g) or a 7-day course of doxycycline (100mg twice daily). Doxycycline is now the preferred treatment in most UK guidelines, as it has been shown to be slightly more effective. Treatment is simple, quick, and effective when the infection is caught early. All recent partners should also be tested and treated.
The case for regular testing
The best protection against chlamydia-related fertility complications is regular testing and prompt treatment. BASHH recommends annual chlamydia testing for all sexually active people under 25, and for older people with new or multiple partners. The National Chlamydia Screening Programme (NCSP) in England offers free testing in a range of community settings. Early diagnosis means early treatment and no long-term consequences.