- Periodic uterine bleeding in response to cyclical hormonal changes.
- Begins at puberty ends at menopause.
- Most women have 28-day cycle period. Length is about 2-7 days.
- Structures involved: hypothalamus, pituitary gland, ovaries and uterus.
- The cycle consists of :
a. Menstrual phase: days 1-5
- Endometrial lining is shed.
- Luteinizing hormone (LH), estrogen and progesterone at their lowest level
- Follicle stimulating hormone (FSH) increases; that Graafian follicle begins maturing.
- Uterine lining grows due to increase estrogen ; it thickens by 8-10 folds.
- Glands and vascularization are developed 3-4 days before ovulation.
- Estrogen is high and progesterone is low.
- Release of mature, non fertilized ovum.
- Spinnbarkeit - stretchable cervical mucus.
- Uterus is prepared for implantation.
- Corpus luteum produces large quantities of estrogen and progesterone.
- If fertilization takes place, implantation occurs 7-10 days post fertilization. Trophoblast produces human chorionic gonadotropin (HCG).
a. Premenstrual or Ischemic Phase: days 24-28
- No fertilization takes place.
- Endometrial arteries constricts; corpus luteum regresses, uterus shrinks.
- Decreased estrogen and progesterone.
- Menstrual concerns are:
Menorrhagia - excessive menstruation.
Menopause - cessation of menses.
Amennorhea - absence of menstruation.
Dysmenorrhea - painful, difficult menstruation.
