What causes blocked fallopian tubes?

Causes of Blocked Fallopian Tubes

Pelvic inflammatory disease (PID) is the primary cause of blocked fallopian tubes, most commonly resulting from sexually transmitted infections like Chlamydia trachomatis and Neisseria gonorrhoeae. 1, 2

Main Causes of Tubal Blockage

Infectious Causes

• Sexually transmitted infections (STIs):

  • Chlamydia trachomatis - most common infectious cause 1
  • Neisseria gonorrhoeae
  • These infections can ascend from the cervix to the upper reproductive tract, causing inflammation and scarring

• Pelvic inflammatory disease (PID):

  • Often a consequence of untreated STIs
  • Can be symptomatic or asymptomatic ("silent PID") 1
  • Causes tubal scarring and occlusion at the fimbrial end, leading to hydrosalpinx 2
  • Many women with tubal-factor infertility report no prior history of PID, suggesting unrecognized or subclinical infections 1

Non-infectious Causes

• Endometriosis - can cause peritoneal adhesions and tubal damage 1
• Previous abdominal or pelvic surgery - resulting in adhesions 2
• Ruptured appendix - causing peritonitis and subsequent adhesions 3
• Tubal spasm - functional rather than anatomic obstruction 4
• Submucosal fibroids - can obstruct the proximal (cornual) portion of tubes 4
• Synechiae (intrauterine adhesions) - can block tubal ostia 4
• Salpingitis isthmica nodosa - nodular thickening of the isthmic portion of the tube 4

Pathophysiology of Tubal Blockage

Mechanism of Damage

1. Inflammation Process:

   • Initial infection causes acute inflammation
   • Repeated or persistent infections lead to chronic inflammation
   • Results in scarring and adhesions within and around the tubes 1

2. Types of Blockage:

   • Distal blockage (most common) - occlusion at the fimbrial end leading to hydrosalpinx 2
   • Proximal blockage - occurs at the uterine end (cornual/interstitial portion) in about 15-20% of cases 5, 6
   • Mid-tubal blockage - less common, often due to salpingitis isthmica nodosa

3. Progression to Hydrosalpinx:

   • When the distal end becomes occluded, fluid accumulates
   • The tube becomes progressively distended
   • This creates a hostile environment for embryo implantation and can leak toxic fluid into the uterine cavity 2

Diagnostic Considerations

Clinical Presentation

• Often asymptomatic until infertility occurs
• May present with pelvic pain, abnormal vaginal discharge, or menstrual irregularities in cases of active PID 1
• History of previous PID, STIs, pelvic surgery, or endometriosis should raise suspicion 1

Diagnostic Methods

• Hysterosalpingography (HSG) - gold standard for evaluating tubal patency (65% sensitive, 85% specific) 1, 2
• Transvaginal ultrasound - 86% sensitive for detecting hydrosalpinx 1, 2
• Hysterosalpingo-contrast sonography (HyCoSy) - alternative to HSG, 91% accurate compared to laparoscopy 1, 2
• MRI - useful when ultrasound findings are inconclusive (75.6% accuracy) 1, 2
• Laparoscopy with chromopertubation - definitive diagnostic method 1

Prevention Strategies

• Early and appropriate treatment of STIs and PID 1
• Regular STI screening for sexually active individuals 1
• Prompt treatment of partners of infected individuals 1
• Use of barrier contraception to prevent STIs 7
• Antibiotic prophylaxis during certain gynecological procedures 1

Clinical Implications

• Blocked fallopian tubes account for approximately 25% of all infertility cases 2
• Women with a history of PID have a 7-10 times higher risk of ectopic pregnancy 7
• Hydrosalpinx significantly reduces IVF success rates by creating a hostile environment for embryo implantation 2
• Early diagnosis and treatment of PID is critical to prevent long-term sequelae such as tubal infertility 1

Understanding the causes of fallopian tube blockage is essential for appropriate prevention, diagnosis, and management strategies to preserve fertility and prevent complications like ectopic pregnancy.