A hysterosalpingogram (HSG) is an X-ray dye test used to diagnose problems related to fertility. During an HSG, an X-ray records images of your uterine cavity and fallopian tubes while they’re filled with a special dye. An HSG can help your provider spot issues in your reproductive anatomy that may prevent you from getting pregnant. These issues include blocked fallopian tubes and an irregularly shaped uterus.A hysterosalpingogram is an X-ray dye test that allows your provider to see your uterus and fallopian tubes. It can help your provider diagnose fertility problems arising from having blocked fallopian tubes.