Tubal factor infertility and hydrosalpinx

Each fallopian tube is a narrow channel with a finger-like fringe at the ovary end. After ovulation the fringe sweeps the egg into the tube, and tiny hair-like cilia lining the tube move it along while sperm travel the other way. Fertilisation usually happens inside the tube, and the early embryo then spends a few days travelling to the womb.

This means a tube does not need to be completely closed to cause trouble. Scarring that stiffens the tube, damage to the lining, or adhesions that pull the fringe away from the ovary can all interfere with that journey even when dye appears to pass through on a test.

The NHS describes pelvic inflammatory disease as an infection of the womb, tubes and ovaries, most often caused by sexually transmitted infections such as chlamydia or gonorrhoea, though other bacteria can be responsible, particularly after procedures that open the cervix. Left untreated it can scar the tubes and raise the risk of reduced fertility and ectopic pregnancy. Some people never recall having symptoms before the damage is found.

Other causes include previous pelvic surgery, burst appendix or bowel inflammation that leaves adhesions, endometriosis affecting the ovaries or tubes, and fibroids that block the tube openings. Sterilisation is a deliberate form of tubal blockage.

• Pelvic inflammatory disease, including infection that went untreated or was never diagnosed.

• Previous surgery in the pelvis or abdomen that left scar tissue.

• Endometriosis involving the tubes or ovaries.

• Fibroids near the tube openings.

• Earlier ectopic pregnancy or tubal surgery.

When the fringed end of a tube seals shut, fluid produced by the tube lining has nowhere to go, and the tube swells. The result is a hydrosalpinx. It may cause a dull pelvic ache, but many people have no symptoms and the finding often comes from a fertility scan.

The concern is not only that the tube is blocked. The fluid can drain back towards the womb and may interfere with the lining that an embryo needs to settle into. The HFEA states that doctors may recommend removing the affected tube because this has been shown to improve the chance of successful IVF, and that mild cases can sometimes be dealt with by keyhole surgery on the tube instead.

The NHS lists three main ways to check tubal patency. Hysterosalpingo-contrast-ultrasonography uses fluid passed into the womb while a transvaginal scan watches whether it moves through the tubes. A hysterosalpingogram does the same job with X-ray dye. Laparoscopy is keyhole surgery in which a camera is passed through a small cut in the abdomen so the surgeon can look at the pelvis and test the tubes directly, and treatment can sometimes be done in the same operation.

A chlamydia test is part of the work-up, because infection history changes both the diagnosis and the safety of any instrumentation. The results decide which route is sensible: tube repair, removal, or going straight to IVF.

The HFEA explains that slight scarring or a potentially reversible blockage may be treated surgically, and that adhesions covering the ovary can be freed with keyhole surgery. It also cautions that surgery is not guaranteed to restore fertility, suggests trying to conceive naturally for a period after surgery before moving to IVF, and warns about the raised ectopic risk after tubal surgery.

IVF bypasses the tubes altogether because eggs are collected from the ovary and embryos are placed in the womb. The HFEA lists blocked or damaged tubes among the commonest reasons IVF is advised. The decision between repair and IVF depends on the extent of damage, age, ovarian reserve, whether sperm quality is normal, and what the couple wish to try.

• Tube surgery may suit mild disease in younger women with otherwise good fertility.

• Salpingectomy (removal of a hydrosalpinx) is discussed before IVF when the tube is fluid-filled.

• IVF is the usual route when damage is extensive or other fertility factors are present.

GPs usually begin with basic tests and refer to a fertility service. The NHS notes that IVF funding is decided by local integrated care boards and varies across the UK, and that eligibility rules can include age and other criteria. Anyone who has been told they have blocked tubes should ask their clinician whether that changes the point at which referral and treatment can start.

Severe one-sided pelvic pain, shoulder-tip pain, fainting or heavy bleeding in early pregnancy can mean an ectopic pregnancy and need emergency care by calling 999 or going to A&E. Fever with worsening pelvic pain, especially after a procedure or a new partner, should be assessed urgently by your GP or NHS 111.