Sono HSG (ultrasound hysterosonosalpingography) is a diagnostic method for the examination of tubal patency. Because this method is safe and simple, it is the first-choice method to examine tubal patency. Previously, tubal patency was tested mostly with X-ray hysterosonosalpingography (Rtg HSG), however, the radiation poses a potential danger not only for patients but also for clinicians who perform medical examinations.
Fallopian tubes are very delicate structures that cannot be detected with conventional ultrasound. In Sono HSG, a contrast agent is injected in the catheter placed through the uterine cavity’s cervical canal and is used to visualize fallopian tubes. Besides liquid contrast agent, foam can also be used for the visualization of fallopian tubes and tubal patency testing.
In addition to Sono HSG, tubal patency can be examined during laparoscopy. Since laparoscopy is a surgical procedure performed usually under general anesthesia, it is recommended only in cases where patients have other indications for the laparoscopy (mostly endometriosis indications).
A fallopian tube patency test is recommended for women who did not achieve pregnancy during one year of unprotected intercourse, and are candidates for timed intercourse or insemination. In around 20% of women undergoing fallopian tube patency test, damaged or blocked tubes will be found and tubal factor infertility will be diagnosed. Even when the test shows patent fallopian tubes, the possibility of the damaged tubes still exists and pregnancy should be planned in the realistic time frame.
Before examination, negative cervical swabs are recommended.
Sono HSG is performed after the period, and before ovulation; that is between the 6th and 12th day of the menstrual cycle. The examination is painless, especially in patients with patent tubes, and a certain degree of pain usually occurs in patients who have damaged tubes. Analgesics such as ibuprofen might be recommended as preparation for sono HSG, around one hour before examination.
After the catheter is placed in the uterus, on the bottom of the catheter bubble is formed so that the catheter cannot fall out from the uterus during examination. Blowing the bubble causes unpleasant sensations in most women, similar to menstrual cramps. Through a catheter contrast agent is injected, and the physician monitors contrast agent movement in the uterus with the ultrasound, as well as its passing through the tubes. The examination takes several minutes.
There is a small risk (around 1%) of infection after sono HSG. In routine practice, antibiotic therapy during or after the examination is not necessary but is recommended in women diagnosed with hydrosalpinx–augmented fallopian tubes filled with liquid.
Several studies have found a higher rate of spontaneous pregnancy 12 to 24 months after sono HSG.
Besides fallopian tube patency testing, sono HSG can be used to examine the morphology of the uterine cavity (anomalies, submucosal myoma, polyps, accretions – synechia). In 15% of the cases, the examination can give false positive results – the fallopian tubes are not shown because of the “tubal spasms”. A spasm is a transient physiological condition.
If the fallopian tubes are patent, timed intercourse or insemination can be recommended.
