HyCoSy stands for Hysterosalpingo Contrast Sonography. This procedure is to assess the patency of fallopian tubes. Your doctor will insert a speculum to be able to pass a small catheter into the womb. Then small amount of fluid is passed into the cavity of the womb to go through the tubes. This passage is assessed by having transvaginal ultrasound scan. The procedure it not painful. You may experience some mild cramps during the passage of fluids. The cavity of the womb is also assessed for the shape and presence of any abnormality.