This observational case series in 65 premenopausal women with abnormal uterine bleeding evaluated whether transvaginal ultrasound followed by saline infusion sonohysterography (SIS) prevented unnecessary hysteroscopy. Although SIS indicated that hysteroscopy was unnecessary in eight women, this benefit was offset by the invasive nature of the scan, the number of endometrial abnormalities falsely detected by SIS and the cost of the additional investigation.