February 29, 2020
About 15% of our patients have tubal factor infertility, meaning we think blocked or diseased Fallopian tubes are the reason they are infertile. We assess the tubes with a hysterosalpingogram (HSG). The HSG is also called the “dye test” because dye is passed up through the uterus and out the tubes. An x-ray is then taken and the radiologist can sort out whether the tubes are open or not.
If the tubes are blocked, the blockage can be in one of three places: proximal, mid or distal. Proximal is near the uterus. Distal is at the end of the tube near the ovaries. Mid is, of course, part way in between. Both tubes can be blocked or just one. Distal tube blockages generally require surgery. Mid tube blockages generally cannot be fixed and the person will need IVF. Proximal tube blockages can often be opened by a tubal cannulation.
Tubal cannulation is the passage of a wire up through the uterus to the blocked tube. The wire is then pushed through the blockage, hopefully opening the tube. I want to talk about proximal tubal blockage/occlusion because I just finished reading a meta-analysis of studies on cannulation of proximal tubal blockages, so it is top of mind.
The meta-analysis is the most recent one, though published in 2017. It analyzed over 1700 patients from 27 studies on the topic. They looked at women who have just one tube blocked proximally, or both tubes blocked proximally, who underwent tubal cannulation to open the tube(s). They then follow these women for several months to see if they got pregnant. Interestingly, if you have cannulation of one tube or both tubes the pregnancy rate is about the same:
6 months after the cannulation 22% of couples are pregnant
12 months after the cannulation 26% of couples are pregnant
24 months after the cannulation 27% of couples are pregnant
There is a 4% risk of an ectopic pregnancy (pregnancy in the tube).
So, tubal cannulation is like a lot of fertility treatments we do: if you are going to get pregnant it will happen within the first 6 months of treatment (generally speaking).
Should you have a tubal cannulation? If you are older or have a low egg count you might not have time to wait to see if the cannulation has worked. These patients should consider IVF. If you are younger and the rest of your fertility testing is normal (normal uterus, good egg count, normal sperm), then you should consider cannulation. In BC tubal cannulation is covered by our provincial health plan. IVF has a higher pregnancy rate than cannulation but comes with cost.
It is worth having a conversation with your doctor if your HSG has shown blocked tubes. A cannulation is a simple procedure and might just help you conceive on your own.
Dr. Beth Taylor MD, FRCSC
Reproductive Endocrinology & Infertility
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