The Menstrual Cycle is Not a Medical Diagnosis—It is a Normal Physiological Process
The menstrual cycle itself is not a medical diagnosis but rather a vital sign indicating overall health status 1. You appear to be asking about how to diagnose disorders of the menstrual cycle, not the cycle itself.
Understanding Normal vs. Abnormal Menstruation
The normal menstrual cycle is a physiological process involving coordinated hormonal interactions between the hypothalamus, pituitary, and ovaries, resulting in cyclic uterine bleeding 1. Normal parameters include:
- Cycle length: 21-45 days (95th percentile is 90 days—anything beyond 3 months is abnormal) 2
- Bleeding duration: 3-7 days 1
- Regular ovulatory cycles (though early post-menarche anovulation is common) 1
Diagnosing Menstrual Disorders
When menstrual abnormalities occur, diagnosis requires prospective symptom tracking for at least 2 months using a menstrual calendar 3, 4. This is the foundation of any diagnostic workup.
Diagnostic Framework: The PALM-COEIN Classification
Use the PALM-COEIN system to categorize abnormal uterine bleeding 5:
Structural causes (PALM):
- Polyp
- Adenomyosis
- Leiomyoma (submucosal or other)
- Malignancy and hyperplasia
Non-structural causes (COEIN):
- Coagulopathy
- Ovulatory dysfunction
- Endometrial
- Iatrogenic
- Not yet classified
Essential Diagnostic Workup
For any menstrual disorder, obtain 5, 4:
- Pregnancy test (beta-hCG)
- Thyroid-stimulating hormone (TSH)
- Prolactin level
- Hemoglobin/ferritin (assess for anemia)
- Coagulation screening (when indicated)
- Transvaginal ultrasonography (96-100% sensitivity for structural pathology) 5
- Endometrial biopsy (preferred over D&C—less invasive, safer, lower cost) 5
Common Pitfalls to Avoid
Do not dismiss oligomenorrhea or amenorrhea as "normal variation" in adolescents—amenorrhea exceeding 90 days warrants evaluation even in early gynecologic years 2. Delayed diagnosis risks bone health complications from estrogen deficiency 2.
Do not rely on transabdominal ultrasound alone—it has poor sensitivity for endometrial assessment. Saline infusion sonohysterography offers 96-100% sensitivity and 94-100% negative predictive value 5.
Specific Menstrual Disorder Diagnoses
Premenstrual Disorders
Diagnosis requires 2 months of prospective daily symptom ratings documenting late luteal phase symptoms that resolve with menses 3. Distinguish between PMS (ACOG criteria) and PMDD (DSM criteria) 3.
Ovulatory Dysfunction
Consider these causes during evaluation 5:
- Adolescence, perimenopause, lactation, pregnancy
- Hyperandrogenic conditions (PCOS)
- Hypothalamic dysfunction
- Hyperprolactinemia
- Thyroid disease
- Primary pituitary disease
- Premature ovarian failure
- Iatrogenic/medications
Menstrual-Related Disease Exacerbations
Document symptoms on a menstrual calendar to identify cyclic patterns in conditions like migraine, epilepsy, asthma, or diabetes 6. Medical suppression of ovulation with GnRH agonists can serve both diagnostic and therapeutic purposes 6.