Chlamydia in 2025 – Impact on Fertility, Symptoms & Effective Prevention

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Zappelphilipp Marx•
Chlamydia bacteria under a microscope

Chlamydia is the most common curable sexually transmitted infection (STI). The World Health Organisation estimates that there were about 129 million new infections worldwide in 2020 WHO. Germany has no mandatory reporting system, so precise figures are lacking; specialists estimate roughly 300,000 cases per year RKI estimate. The problem is that most people notice no symptoms, allowing complications such as infertility to develop unseen.

Chlamydia Explained: Causes & Transmission

The infection is caused by the bacterium Chlamydia trachomatis, which targets the mucous membranes of the urethra, cervix, rectum, and throat. Transmission is almost always via unprotected vaginal, anal, or oral sex. During childbirth, an infected mother can also pass the bacterium to her baby, leading to conjunctivitis or pneumonia in newborns.

Symptom Check: How “Silent” Is Chlamydia?

According to the CDC, infections are asymptomatic in around 70–95 percent of women and about 50 percent of men. When symptoms do occur, they usually appear one to three weeks after exposure – by then the bacteria may have spread further.

Chlamydia in Women – Typical Symptoms & Long-Term Effects

Early warning signs (if any):

  • unusual, often watery-pus–like or foul-smelling discharge
  • inter-menstrual or post-coital bleeding
  • pain during intercourse (dyspareunia)
  • burning when passing urine (dysuria)
  • lower-abdominal or back pain

Potential long-term consequences if untreated:

  • PID (pelvic inflammatory disease) – infection spreading to the uterus and fallopian tubes
  • Salpingitis – scarring of the tubes leading to blockage
  • Infertility – reported in up to 40 percent of untreated cases
  • greater risk of ectopic pregnancy, pre-term birth, or miscarriage

Chlamydia in Men – What’s Different?

Possible acute symptoms:

  • clear to pus-like urethral discharge
  • burning or pain when urinating
  • swelling or pain in the testes or epididymis

Typical complications (rare but possible):

  • Epididymitis – inflammation of the epididymis with pain and fever
  • prostatitis or urethral strictures
  • reduced sperm quality, leading to fertility issues
  • Reactive arthritis (Reiter’s syndrome) – inflammation of joints, eyes, and skin

Note: Even men without symptoms can transmit the infection – both partners must always receive treatment.

Untreated Chlamydia: Shared Risks

  • chronic pelvic or lower-abdominal pain
  • infertility in women; reduced fertility in men
  • conjunctivitis or pneumonia in newborns

Prevention That Really Works

  • Condoms – highly effective when used consistently and correctly
  • Routine testing – the CDC advises annual screening for sexually active women up to 25 and risk-based testing thereafter
  • limit the number of sexual partners or agree on shared testing intervals
  • clean sex toys after each use or cover them with a fresh condom
  • pregnant individuals should be tested for chlamydia in the first trimester

Treatment Today – Why Doxycycline Has Replaced Azithromycin

Chlamydia is almost always curable with antibiotics. Updated guidelines favour doxycycline for seven days over a single dose of azithromycin because studies show rising azithromycin resistance and slightly better efficacy for doxycycline. Proven laboratory resistance to tetracyclines or macrolides is still very rare.

Diagnostics & Testing Basics

Test types

  • NAAT / PCR – highly reliable; results within one to two days
  • Rapid test – result in about 20 minutes, but far less accurate (screening only)

Specimen options

  • women: vaginal swab (self-taken or clinician) or first-catch morning urine
  • men: first-catch urine; urethral swab if symptomatic

When to Seek Medical Advice

The WHO defines infertility as the absence of pregnancy after twelve months of unprotected intercourse (after six months if the woman is over 35). Common causes include untreated chlamydia, endometriosis, and hormonal disorders.

  • unexplained discharge, burning, or bleeding — get tested straight away
  • new relationship without up-to-date STI status — both partners should test
  • positive result — treat both partners and abstain from sex for seven days

Take-Home Message

Chlamydia is common, often silent – yet highly treatable. Regular testing, consistent condom use, and prompt antibiotics greatly reduce the risk of serious complications such as infertility. Invest in your sexual health – preventing infection is far easier than dealing with long-term damage.

Disclaimer: Content on RattleStork is provided for general informational and educational purposes only. It does not constitute medical, legal, or other professional advice; no specific outcome is guaranteed. Use of this information is at your own risk. See our full Disclaimer.

Frequently Asked Questions (FAQ)

Chlamydia is a bacterial sexually transmitted infection (STI) caused by Chlamydia trachomatis. It is common, often symptom-free, but fully curable with antibiotics.

Many women have no symptoms. Possible clues include unusual discharge, spotting, discomfort during sex or urination, and lower-abdominal pain.

Men may notice a clear or pus-like penile discharge, burning when passing urine, or swollen, tender testicles—yet half remain symptom-free.

Mostly through unprotected vaginal, anal or oral sex. It can also pass from an infected mother to her baby during birth.

Yes. Untreated infection can cause pre-term birth and eye or lung infections in newborns. Routine antenatal screening is therefore recommended.

In women it may scar the fallopian tubes; in men it can lower sperm quality. Both can lead to infertility if left untreated.

Test after a new partner, if you have symptoms, if a partner tests positive, or during pregnancy. The UKHSA advises annual screening for sexually active women under 25.

NAAT / PCR is the gold standard—over 95 per cent accurate, with results in one to two days. Rapid tests give results in 15–20 minutes but are much less sensitive.

Women provide a self-taken or clinician-taken vaginal swab, or first-catch urine. Men provide first-catch urine; a urethral swab may be taken if symptoms are present.

First-line treatment is doxycycline 100 mg twice daily for seven days. A single 1 g dose of azithromycin is an alternative but less favoured owing to rising resistance.

Cure rates are excellent if the full course is completed and all recent partners are treated at the same time.

It can progress to pelvic inflammatory disease (PID), chronic pelvic pain, ectopic pregnancy, or permanent fertility problems in both sexes.

Definitely. Partners from the past 60 days should be tested and treated to prevent reinfection.

Seven days after starting doxycycline (or seven days after azithromycin) you are considered non-infectious. Avoid sexual contact during this period.

Yes. Previous infection gives no lasting immunity, so condoms and regular STI checks remain vital.

Consistent, correct condom use greatly reduces the risk of chlamydia, gonorrhoea, HIV and other STI and is central to safer sex.

Pelvic inflammatory disease is an ascending infection of the uterus, tubes and ovaries. Up to 30 per cent of untreated female chlamydia cases develop PID.

Yes. The bacteria can infect the throat and rectum. Using condoms or dental dams lowers the risk.

Not yet. Several protein and mRNA candidates are in clinical trials, but no licensed vaccine is currently available.

Combined testing for gonorrhoea, syphilis, HIV and trichomoniasis is sensible, as co-infections are common and can complicate treatment.