What HSG is
A hysterosalpingogram (HSG) is a fluoroscopic X-ray procedure in which a water- or oil-based contrast dye is passed through the cervix into the uterus and fallopian tubes. It evaluates whether the fallopian tubes are open (tubal patency) and outlines the shape of the uterine cavity.
When it is performed
HSG is typically scheduled after menstrual bleeding has ended and before ovulation, often about 7–10 days after the first day of your period. This timing reduces the chance of performing the test during an early pregnancy.
What it can reveal
In addition to tubal patency, HSG can reveal intrauterine adhesions, endometrial polyps, submucosal fibroids, or a uterine septum by outlining the shape of the uterine cavity.
HSG vs. hysteroscopy vs. sonohysterogram
HSG uniquely assesses the fallopian tubes. Hysteroscopy directly visualizes the uterine cavity through a thin telescope but does not evaluate the tubes. Sonohysterogram uses saline and ultrasound to evaluate the uterine cavity without radiation, and also does not evaluate the tubes.