Here is a some good description on HSG from my clinic's website:
The sonohysterogram (SHG) is similar to the hysterosalpingogram (HSG) in that it helps us to evaluate the uterine cavity. But, with the SHG, saline rather than an X-ray dye is instilled into the uterus and the progress of the saline is tracked with ultrasound rather than X-ray. The SHG provides clear views of the uterine muscle along with the endometrial cavity. Thus, we are able to see abnormalities like fibroids by SHG that cannot be seen by HSG. Also, by using ultrasound, we can utilize new 3D ultrasound technology that allows us to rotate the image of the uterus to obtain the best diagnostic picture. Even the most subtle abnormalities can be clearly seen with SHG allowing for accurate treatment planning. Unfortunately, the SHG does not provide any information on the fallopian tubes so it cannot replace the HSG.
Why would your Dr. recommend a SHG?
Well the way I see it, your RE clinic should perform this test to determine the following thing:
1. Do you have any uterine abnormalities that may be causing your infertility?
A few years ago it was with a combination HSG/SHG that we found a fibroid that was likely to be a source our infertility. After it was surgically removed, a new SHG test showed some adhesions (scar tissue) and polyps that may cause PID (pelvic inflammatory disease). This can also affect whether or not you can become and stay pregnant. Some ladies who have unfortunately miscarried have had fibroids found that may been attributed to their loss. I don’t have endometriosis or PCOS, so I can’t talk on those subjects, but if anyone has a blog that discusses the methods of their diagnosis, I would be happy to provide a link.
Here is a good web article about using ultrasound to diagnose IF problems:
How does an SHG feel? What is involved from the patient's point of view?
Going through a SHG for me was relatively easy. You are asked to arrive at the doctor’s office with a full bladder. OK. Well, good point. Trying to go through your day getting enough liquid in your system to make a “full bladder” without overdoing it, desperately hoping you don’t piddle on the floor like some excited cocker spaniel can be a bit tricky. But I digress…