What initial diagnostic test is recommended for a patient experiencing bleeding after menopause?

The initial diagnostic test recommended for a patient experiencing bleeding after menopause is an endometrial biopsy. This procedure is particularly important because postmenopausal bleeding can be a symptom of significant pathologies, including endometrial hyperplasia or endometrial cancer. An endometrial biopsy allows healthcare providers to obtain a sample of the endometrial tissue for histological analysis, enabling the diagnosis of any abnormal changes or malignancies that might be present.

In contrast, while a pelvic ultrasound can be useful for visualizing the uterus and identifying structural abnormalities, it does not provide tissue for definitive diagnosis, making it less suitable as an initial diagnostic test in this scenario. Hysteroscopy, which allows direct visualization of the uterine cavity, is typically reserved for cases where further investigation is warranted after initial findings, or if treatments are needed. A Pap smear is primarily used for cervical cancer screening and is not indicated for assessing postmenopausal bleeding, as it focuses on the cervical cytology rather than the endometrial lining. Thus, an endometrial biopsy is the most appropriate and effective first step in the evaluation of bleeding after menopause.