Proximal tubal occlusion involves a blockage at the junction of the uterus and the tube. The diameter of the fallopian tube is quite small within the uterine wall. The tube increases in diameter as you move distally towards the opening near the ovary. The “spasm” of uterine muscles during the HSG may constrict or occlude one or both of the fallopian tubes. Small plugs of material, usually thought to be mucus or proteinaceous debris, can also occlude the proximal tube(s) where it is very narrow within the uterus. Permanent proximal tubal damage due to scarring inside the tube is uncommon.
Available Case Reports:
If there is occlusion of only one of the tubes proximally (at the junction of the uterus), then the patient and infertility specialist have a difficult decision.
The improvement in fertility seen when there are 2 patent (open) tubes versus only 1 patent tube with a nonfilling other side has not been extensively studied but appears to be small (when examined in one report involving a small number of patients the fertility rates were 58% versus 50%). This result implies that the second tube is nonfilling either due to a transient process such as spasm or due to a significant difference in resistance to flow between the sides (the diameter of the opening on the filling side may be slightly greater). In either of these situations the media travels preferentially through the path of least resistance and no longterm pathology is present.
Pathology exists when the nonfilling side is occluded with a mucus or proteinaceous plug. If this is the case, the plug can often be removed relatively easily with a nonsurgical procedure similar to the HSG during which the physician (usually a radiologist or infertility specialist) passes a small catheter (tube) into the uterine cavity to the tubal ostia (opening) and mechanically flushes the plug out of the way with dye or dislodges the plug with the catheter. This procedure, called proximal tubal catheterization, is usually successful at opening the plugged tube about 60-80% of the time.
A pelvic process that should be addressed surgically may also occlude the nonfilling tube. If there are severe pelvic adhesions, endometriosis, or tubal luminal adhesions following a pelvic infection then the tube may be occluded all the way back to its origin at the uterus. Such extensive disease is only likely to occur in patients with a suggestive history. However, there certainly are some (uncommon) situations where the HSG finding of one occluded tube is the initial indication of more extensive disease.
The patient’s history (including prior infections in the pelvis, abdominal or pelvic surgery, IUD use) and the couple’s comfort level concerning the risks and benefits of each of these alternative diagnostic and treatment plans should be used to guide the decisions that must be made. The primary downside of trying to conceive for 3-6 months despite one nonfilling tube is that you may delay other appropriate care. In a young couple this may be acceptable. In a couple where the woman is in her late 30s or 40s one could consider a more aggressive approach.