Menopause can happen naturally as a result of physiological changes during the ageing process. It can also be induced surgically in women who have their ovaries removed (oophorectomy) with or without the removal of the uterus (hysterectomy).
Under the influence of pituitary gland hormones FSH (follicle stimulating hormone) and LH (luteinising hormone), the ovaries release the egg every month and secrete the sex hormones – oestrogen and progesterone. These hormones act on the lining of the womb preparing it for pregnancy in case the egg gets fertilised by the sperm. In cases where fertilisation does not take place, the lining of the womb is shed, which we know as “periods”.
As part of the ageing process, the eggs or the oocytes in the ovary gradually get depleted. This causes an increase in the levels of FSH and LH and a decrease in the levels of oestrogen. The oocyte depletion with the resultant hormonal changes leads to the cessation of menses and the absence of fertility in women. It is the decreased circulating level of oestrogen which is responsible for the physical changes that happen during menopause.
Surgical menopause occurs when the ovaries are removed. The abrupt and sudden withdrawal of the hormones can sometimes lead to severe menopausal symptoms. Removal of the uterus with the conservation of the ovaries does not cause menopause. These women will not have periods due to the removal of the uterus but the ovaries will still be functioning. However, they may experience menopause earlier due to some disruption of the blood supply to the ovaries. Menopause can also be induced by chemotherapy or radiation therapy during cancer treatment.
What happens in the body during menopause?
Hormonal changes occur during menopause causing a decrease in the levels of oestrogen and progesterone and an increase in the levels of FSH and LH. These changes cause the cycle to become irregular in the perimenopausal years. The cycle can be shortened, appearing as a two-week cycle, or the flow during periods may become heavy.
Sometimes the period may be missed for a few months; this could be followed by a very heavy period. This happens due to skipped ovulation (release of the egg from the ovary during the middle of the cycle). Once the period has stopped for 12 months, menopause is said to have occurred.