First principle: the tube must transport, not merely be open
Fertilisation occurs in the tube, which must catch, host and transport. Causes of tubal damage recapitulate earlier parts: PID, genital TB, endometriosis, prior pelvic surgery.
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Interpreting the tests
- HSG shows cavity + tubal spill; bilateral proximal block may be spasm/artefact → don't declare permanent occlusion without re‑evaluation.
- Never during active infection (Concept 28). 🚩
- Hydrosalpinx signifies severe disease and reduces IVF success → may need salpingectomy/occlusion before IVF.
- Laparoscopy + chromopertubation is not routine — reserve it for when pelvic pathology (e.g. endometriosis) is otherwise indicated; then assess tubes at the same time.
Cervical factor — mostly historical
Unexplained infertility
Ovulatory + patent tubes + normal semen + no cause (~up to 30%). Reasonable pathway: a limited course (~3–4 cycles) of ovarian stimulation + IUI, then IVF if unsuccessful — tailored to age, duration and reserve.
Pitfalls
- Calling bilateral proximal HSG block "permanent."
- Ordering postcoital tests routinely.
Pearls
- 🎯 HSG shows patency; beware proximal spasm; treat hydrosalpinx before IVF.
- 🩺 "Unexplained" is a positive, actionable label — offer stimulation + IUI, then IVF.
Next → When to reach for each assisted‑reproduction tool (Concept 33).