Transvaginal Ultrasound

A transvaginal ultrasound is an imaging procedure where a small ultrasound probe is inserted into the vagina to produce detailed, close-up images of the ovaries, uterus, and surrounding structures, providing superior visualization compared to abdominal ultrasound. In PCOS evaluation, transvaginal ultrasound is used to identify the characteristic polycystic ovary morphology: 12 or more small follicles per ovary (or 20+ under updated criteria) and/or increased ovarian volume greater than 10 mL. While an important diagnostic tool, polycystic-appearing ovaries on ultrasound alone do not confirm PCOS—the findings must be interpreted alongside menstrual history and androgen testing as part of the Rotterdam Criteria.