Menstruation

The natural monthly cyclical shedding and discharge of endometrial tissue with blood and uterine secretions in nonpregnant, reproductive-age females, occurring due to withdrawal of progesterone after regression of the corpus luteum at the end of an ovulatory cycle.

Factors that may alter the menstrual cycle

• Physiological causes

  • Pregnancy

  • Menopause

  • Perimenopause

  • Lactation

• Hormonal and endocrine causes

  • Polycystic ovary syndrome (PCOS)

  • Thyroid disorders

  • Hyperprolactinemia

  • Hypothalamic–pituitary dysfunction

• Lifestyle and environmental factors

  • Psychological stress

  • Significant weight gain or weight loss

  • Eating disorders

  • Excessive physical exercise

  • Major changes in sleep patterns

• Structural uterine causes

  • Uterine fibroids

  • Endometrial polyps

  • Adenomyosis

  • Uterine structural abnormalities

• Inflammatory and gynecological causes

  • Endometriosis

  • Pelvic inflammatory disease

  • Chronic endometrial inflammation

• Medication-related causes

  • Hormonal contraceptives

  • Antipsychotics and other medications affecting prolactin

  • Chemotherapy

• Systemic and medical causes

  • Chronic illness

  • Liver disease

  • Kidney disease

  • Malnutrition

  • Severe metabolic stress