Blocked Fallopian tubes account for about 20% of female infertility cases, and the tubes are delicate, dynamic structures that link the ovaries to the womb. They’re easily damaged, and the tubes perform essential roles in all natural pregnancies by supporting and transporting an embryo to the womb. Any excess mucus, scar tissue or distortion in a tube’s structure can prevent or delay this vital journey.
Women need at least one patent (open and functional) tube for a natural pregnancy, and one tube being blocked doubles the expected time to get pregnant. If both tubes are blocked, conceiving becomes impossible without IVF, and all tubal abnormalities increase the risk of ectopic pregnancies.
Seven causes of Tubal Blockage
Pelvic inflammatory disease (PID)
PID is the main cause of blocked Fallopian tubes, and the inflammation can create scar tissue and adhesions which distort tubes; and while PID is usually due to sexually transmitted infections, the causes include:
- Sexually transmitted infections by bacteria, viruses, fungi or parasites
- A miscarriage or termination
- Endometritis (inflammation of the endometrial lining of the womb)
- Abdominal infections such as peritonitis or appendicitis
- Salpingitis (inflammation of the Fallopian tubes)
PID is often symptom-free, or the symptoms are mild, with slight lower abdominal pain and tenderness that’s worse with pressure and possibly a low-grade fever. Laparoscopy that shows clear evidence of PID comes as a complete surprise to about two-thirds of the women involved, and PID infections gradually reduce fertility by making the tubes less functional:
- 12% are infertile after one infection
- 23% are infertile after two infections
- 53% are infertile after three infections
Mucus obstructing the Fallopian tubes
Excess mucus is usually due to problems with the “peg” cells (uterus and fallopian tubes) that line the tubes. The peg cells release nutrient-rich fluids that are essential to nourish sperm or embryos in the tubes. But if the secretions are too thick (or too much), they can accumulate and form a sticky plug that blocks the tube. This situation is something Fluids PFP women are particularly vulnerable to.
Alternatively, tubes can get blocked if the “cilia” cells fail to move fluids enough to keep the tube open. These cells have hair-like structures that beat to transport fluids (or an embryo) toward the womb. This issue tends to affect Flow and Tired PFP women the most, but it can be a combination of factors, but the tubes have become blocked due to the person’s dynamics rather than an infection.
The usual cause here is tubal ligation operations that are carried out to sterilize the woman. However, it’s possible for any lower abdominal surgery (such as an appendix removal) to trigger adhesions that block the Fallopian tubes.
After IUD use
Intrauterine devices (IUDs) like the Merina coil, which are inserted into the womb, can trigger inflammation in the womb lining that spreads into the delicate tissue of the tubes. The tube structure can be distorted, and the peg and cilia cells’ function can be disrupted with mucus plugs forming.
Endometriosis usually consists of connective or vascular tissue, and one of the most common sites for the lesions is at the ends of the Fallopian tubes or around the ovary. The endometriosis lesions can cause the finger-like ends of the tubes to clump together or create adhesions in the tubes.
Torsion involves the twisting (and blocking) of a Fallopian tube, and the usual cause is that an ovary has become too heavy for the ligaments to hold it in place. The heavy ovary drags the tubes out of position, distorting their shape and closing the space within them. Large “functional cysts” are the prime suspects, but IVF stimulation drugs dramatically increase the number of large follicles in ovaries and significantly raise the risk of this happening.
A hydrosalpinx can form after infections, and they grossly distort a Fallopian tube. They dramatically reduce the possibility of embryos reaching the womb and reduce natural and IVF fertility. The presence of a hydrosalpinx usually requires surgery to tie the tube before IVF proceeds to prevent the fluid in them from draining into the womb and stopping implantation.
ii By BruceBlaus – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?