Menopause typically occurs around the age of 51, marking the natural end of a woman's reproductive years.

However, when menopause happens significantly earlier—before the age of 45—it is classified as early menopause.

Biological and Genetic Factors

The most fundamental cause of early menopause lies in the premature decline of ovarian activity, often referred to by clinicians as primary ovarian insufficiency. In these cases, the ovaries cease producing the hormones necessary to regulate the menstrual cycle and fertility.

While the exact biological mechanisms remain partially enigmatic, genetic predisposition plays a significant role. Genetic disorders, including familial patterns of early menopause, also demonstrate the hereditary nature of this phenomenon.

Autoimmune factors contribute notably to ovarian dysfunction. In certain instances, the body's immune system mistakenly targets and damages ovarian tissue, disrupting hormone production. Conditions such as thyroid disease, Addison's disease, and mumps have been linked to autoimmune-related early menopause. These immune attacks on ovarian follicles lead to a gradual or sudden loss of fertility and hormone balance.

Medical and Surgical Causes

Medical interventions form a substantial category of early menopause triggers. Cancer treatments such as chemotherapy and radiation therapy, especially when targeting the pelvis or brain, can severely damage ovarian tissue. The destruction inflicted by these treatments may be temporary or permanent, depending on dosage and timing with respect to age.

Certain medications that suppress estrogen activity, such as those used to prevent or treat hormone-sensitive cancers, can precipitate early menopause. These antiestrogenic agents reduce estrogen levels systemically, simulating the hormonal milieu of menopause regardless of ovarian status.

Lifestyle and Environmental Contributors

Lifestyle factors also impact the timing of menopause. Toxic components accelerate the depletion of ovarian follicles and impair estrogen biosynthesis. Nutritional status, particularly being underweight, has been linked to an increased risk of premature menopause.

Adequate body is critical for estrogen synthesis via peripheral conversion; insufficient fatty reserves may disrupt hormone levels and ovarian function.

Unknown and Idiopathic Origins

Despite advances in medical science, approximately 90% of early menopause cases remain idiopathic. The ovaries simply fail to function prematurely with no identifiable cause. This idiopathic nature complicates prediction and prevention strategies, demanding comprehensive clinical evaluation and long-term monitoring.

Dr. Jerilynn C. Prior, Canadian endocrinologist and medical doctor specializing in menstrual cycles and the effects of hormones on women's health, states, "We must differentiate between these two phases (menopause and perimenopause) if we're going to deliver proper care and be accurate scientists."

Early menopause results from a complex interplay of genetic, autoimmune, medical, surgical, and lifestyle factors leading to premature ovarian failure and hormone deficiency. Early recognition and expert care by specialists such as reproductive endocrinologists are critical to managing symptoms and preventing associated health issues like osteoporosis and cardiovascular disease.