Menopause - Causes
There are several known causes of early menopause, although sometimes the cause remains unknown.
Genetics: When there is no obvious medical reason for early menopause, the cause often lies in the genes. If a woman is able to find out when her mother started menopause can provide clues as to when she will start her own.
Lifestyle factors: Smoking can contribute to early menopause due to its anti-oestrogen effects. Several studies have shown that long-term or regular smokers are likely to experience menopause sooner than the average age of occurrence.
Body mass index (BMI): Oestrogen is stored in the body's fat tissue. Very thin women have fewer oestrogen stores, which will reduce faster. A higher BMI could cause a late onset of menopause.
Autoimmune diseases: Premature menopause can be a symptom of an autoimmune disease. These occur when the immune system itself attacks the body. Damage caused by some autoimmune diseases, such as the thyroid disease can affect the ovaries.
Epilepsy: Epilepsy is a disorder of fits that originates in the brain.
Natural decline of reproductive hormones: When a woman is in her late 30s, ovaries start making less oestrogen and progesterone (hormones that regulate menstruation); as result, her fertility decreases. In her 40s, however, menstrual periods may become longer or shorter, heavier or lighter and either more or less frequent, until, eventually, approximately by age 51 she may have no more periods.
Hysterectomy: A hysterectomy that removes the uterus but not the ovaries (partial hysterectomy) usually does not cause immediate menopause. But surgery that removes both the uterus and the ovaries (total hysterectomy) does cause menopause, without any transitional phase.
Chemotherapy and radiation therapy: These cancer therapies can induce menopause, causing symptoms such as hot flushes during or shortly after the course of treatment.
Primary ovarian insufficiency: About 1% of women experience menopause before age 40 (premature menopause).