🧱 The First Principles of Abnormal Uterine Bleeding (AUB)
- Normal menstrual bleeding occurs only when 3 systems function together:
- Hypothalamus-Pituitary-Gonadal Axis
- Hypothalamus releases GnRH
- Pituitary releases FSH and LH
- FSH stimulates follicle development
- LH triggers ovulation
If this system fails, ovulation may not occur, irregular bleeding happens
- Normal uterine bleeding involves regular menstrual cycle of 24 - 38 days, with duration ≤8 days and ≤80 mL menstrual blood loss per cycle.
- Abnormal uterine bleeding occurs when there is disruption of normal menstrual physiology, resutling in bleeding that is irregular in timing, duration, frequency or volume.
- Abnormal uterine bleeding is classified using the FIGO PALM-COEIN system into structural causes (Polyps, Adenomyosis, Leiomyoma, Malignancy) and non-structural causes (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not otherwise classified)
🔠 Definitions
📚 Classification
🌱 Aetiology
⚡ Clinical features
🔎 Risk Factors
📄 DDx
🔎 Investigation
💊 Management
♟️ References
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👨👨👧👧 Created by: The 1PM Team
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Disclaimer: This episode was recorded on 1 May 2026. At the time of recording, the condition now known as Polyendocrine Metabolic Ovarian Syndrome (PMOS) was referred to as Polycystic Ovary Syndrome (PCOS). Following the official nomenclature change announced on 12 May 2026, the term PMOS is now preferred. References to "PCOS" in this episode reflect the terminology that was in use at the time of recording.
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