References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Untreated chlamydia can cause pelvic inflammatory disease (PID) in women, which can scar the fallopian tubes and lead to infertility or ectopic pregnancy. In men, chlamydia can cause epididymitis, which rarely affects fertility. The key message is that prompt treatment prevents virtually all fertility complications — regular testing catches chlamydia before damage occurs.
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How Chlamydia Affects Fertility
| Stage | What Happens |
|---|---|
| 1. Infection | Chlamydia infects the cervix (often silently) |
| 2. Ascending infection | Bacteria spread to uterus and fallopian tubes |
| 3. PID develops | Inflammation and scarring of the tubes |
| 4. Fertility impact | Blocked tubes prevent egg meeting sperm |
Risk Factors for Complications
- Delayed diagnosis
- Repeated infections
- Not treating partners (causing reinfection)
- Having symptoms but not seeking care
Prevention
- Annual chlamydia screening if under 25
- Testing with each new partner
- Prompt treatment of positive results
- Partner treatment to prevent reinfection
The Good News
- Most single episodes of chlamydia don’t cause infertility
- Prompt treatment prevents complications
- Even after PID, many women conceive naturally
- Assisted reproduction offers further options
Read more: What is chlamydia? | STIs and infertility | What is PID?
Frequently Asked Questions
Will one chlamydia infection make me infertile?
Very unlikely with prompt treatment.
Can men become infertile from chlamydia?
Rarely — epididymitis can affect fertility in severe cases.
How do I protect my fertility?
Test regularly and treat promptly.
Related reading
- Can You Get Chlamydia From Kissing?
- Can You Have Chlamydia and Test Negative?
- How Common Is Chlamydia in the UK?
- Multi-Site STI Testing: Genital, Rectal and Throat
- What Is Mycoplasma Genitalium?
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
