The most common cause of abnormal uterine bleeding (AUB) in women of reproductive age is ovulatory dysfunction (anovulation or oligo-ovulation).
Understanding Ovulatory Dysfunction
Ovulatory dysfunction refers to problems with the process of ovulation, where an egg is released from the ovaries. This can manifest as:
- Anovulation: Complete absence of ovulation.
- Oligo-ovulation: Infrequent or irregular ovulation.
When ovulation is disrupted, the normal hormonal balance of estrogen and progesterone is also disrupted. This imbalance can lead to irregular shedding of the uterine lining (endometrium), resulting in AUB.
Prevalence of Ovulatory Dysfunction in AUB
Ovulatory dysfunction is particularly prevalent in two key age groups:
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Adolescents: Approximately 20% of AUB cases in adolescents are attributed to ovulatory dysfunction. This is often due to the immaturity of the hypothalamic-pituitary-ovarian (HPO) axis, which regulates the menstrual cycle.
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Perimenopausal Women: About 50% of AUB cases in women over 45 years old are linked to ovulatory dysfunction. As women approach menopause, their ovaries become less responsive, leading to irregular ovulation.
Other Potential Causes of AUB
While ovulatory dysfunction is the most common cause, it is crucial to remember that AUB can stem from various other factors, including:
- Structural Abnormalities: Polyps, adenomyosis, leiomyomas (fibroids), and malignancy. These are often categorized under the PALM-COEIN classification system for AUB.
- Coagulopathy: Bleeding disorders.
- Endometrial Causes: Endometritis or endometrial hyperplasia.
- Iatrogenic Causes: Medications or intrauterine devices (IUDs).
- Not Yet Classified: When the cause of AUB can't be placed in other categories.
When to Seek Medical Attention
It is essential to consult a healthcare professional if you experience any abnormal uterine bleeding, especially if it is:
- Heavy or prolonged.
- Occurring frequently.
- Happening after menopause.
- Accompanied by other symptoms such as pain or dizziness.
A healthcare provider can perform a thorough evaluation to determine the underlying cause of AUB and recommend appropriate treatment.
