2020 Hong Kong College of Obstetricians and Gynaecologists guideline on investigations of premenopausal women with abnormal uterine bleeding.

Abnormal uterine bleeding in premenopausal women is a common gynaecological symptom and composes of abnormality in the frequency, duration, regularity, and flow volume of menstruation. It could constitute the presentation of various gynaecological malignancies. An appropriate history and physical examination are mandatory to ascertain the diagnosis. Depending on the clinical condition, a complete blood picture, thyroid function test, clotting profile, chlamydia test, cervical smear, and pregnancy test can be performed. Ultrasound should be performed in cases with a pelvic mass, unsatisfactory physical examination, persistent symptoms, or no response to medical treatment. In women aged ≥40 years, an out-patient endometrial biopsy with Pipelle should be performed. In women aged <40 years with risk factors for endometrial cancer, persistent symptoms, or no response to medical treatment, an endometrial biopsy should be performed to rule out endometrial cancer. Hysteroscopy or saline infusion sonohysterography is more sensitive than ultrasound for diagnosing endometrial pathology. Details of the above recommendations are presented.