One of the most common imaging techniques used on women undergoing infertility treatment. Almost all ultrasound examinations performed for purposes of monitoring/diagnosing women with infertility issues are currently carried out by means of a vaginal transducer (a small probe inserted into the vagina). An ultrasound transducer emits acoustic sound waves that bounce back when they hit different types of tissues in the body. These waves are then recaptured by the transducer and sent to the ultrasound computer. The ultrasound transforms these waves into gray scale pictures that are seen on a monitor screen. The texture of the particular tissue that the ultrasound wave traverses or hits determines the way it will look on the monitor. For instance, clear fluids such as urine will appear black while bony structures will appear white. The vaginal transducer is about 15 inches long and 1 inch in diameter. Only about 5 inches will enter the vagina. The procedure is painless for most women as well as harmless. It enables us to see the pelvic organs, including the ovaries and the uterus. It is commonly used to diagnose the presence of ovarian cysts, tumors, uterine fibroids, and pregnancies. It is also used routinely to follow the growth and development of ovarian follicles during ovulation induction with fertility drugs in patients who are undergoing treatment.