The document provides an in-depth overview of amenorrhea, its classifications, causes, and mechanisms, including both primary and secondary forms. It discusses the hormonal interplay involved in menstruation, the diagnostic workup for amenorrhea, and specific syndromes such as Turner syndrome and Mayer-Rokitansky-Küster-Hauser syndrome that can lead to primary amenorrhea. Additionally, it covers the assessment and management strategies for various types of amenorrhea.