Menopause signifies the end of menstruation, typically occurring between 47 and 53. However, when it occurs much earlier in life, it’s a different condition known as Premature Ovarian Insufficiency (POI). Let’s explore what POI is, its causes, and how it differs from typical menopause.
Menopause concept
Defining Premature Ovarian Insufficiency (POI)
Premature menopause, premature ovarian failure, and premature ovarian insufficiency (POI) are terms often used interchangeably. While there’s no universally agreed-upon term, premature ovarian insufficiency is increasingly preferred as it more accurately describes the condition. Unlike typical menopause, which occurs around age 51, POI happens much earlier and doesn’t always result in irreversible ovarian failure. The ovaries may still function intermittently.
Early menopause is defined as menopause occurring before age 45, while POI is generally diagnosed when it occurs before age 40. This means that the ovaries stop producing eggs sooner than expected, sometimes decades earlier. Furthermore, the ovaries produce less estrogen and progesterone, which are critical for women’s health.
POI differs from typical menopause in several ways. Besides occurring at a younger age, ovarian function isn’t always completely lost. This can result in sporadic periods, ovulation, and even pregnancy years after diagnosis. Approximately 5-10% of women with POI can still conceive.
Prevalence of POI
POI affects about 1 in 100 women under 40, 1 in 1,000 women under 30, and 1 in 10,000 women under 20. Spontaneous early menopause affects around 5% of women before age 45. While spontaneous POI affects 1% of women before 40, the rising number of women experiencing iatrogenic POI (caused by surgery or cancer treatments) makes it difficult to determine the exact number of affected women.
Causes of POI
POI can arise from multiple factors, but in most cases (90%), the underlying cause remains unknown. This is termed spontaneous or idiopathic POI. While not knowing the cause can be emotionally challenging, it doesn’t impact the recommended treatment. Some identified causes include:
Autoimmune Diseases: Autoimmune disorders can lead the body’s immune system to attack its own tissues, including the ovaries. This can result in POI and is thought to occur in approximately 5% of women with POI. POI is often linked to other autoimmune conditions like underactive thyroid, type 1 diabetes, and Addison’s disease.
Genetic Factors: Abnormalities in the X chromosome or other genes influencing sex hormone function can cause POI. Multiple genetic defects have been identified, with Turner syndrome (where one X chromosome is missing) being the most common. POI is also associated with rare conditions that tend to run in families, such as Fragile X syndrome and galactosemia. Genetic causes are more prevalent in women with a family history of POI or those diagnosed at a very young age, especially those whose periods never started.
Infection: POI has been reported following infections like mumps, tuberculosis, and malaria, but this is extremely rare.
Surgery: Surgical removal of the ovaries before age 40 is another form of POI. This sudden loss of ovarian hormones can trigger abrupt menopause symptoms. Ovaries may be removed (with or without hysterectomy) for reasons like ovarian cancer, ovarian cysts, endometriosis, or severe premenstrual syndrome. Ideally, such surgeries are planned, allowing for discussions about hormone replacement therapy to minimize menopausal symptoms.
Cancer Treatment: Cancer treatments like chemotherapy or radiotherapy can temporarily or permanently damage the ovaries, leading to POI. The likelihood depends on the chemotherapy drugs, the site of radiotherapy, and the patient’s age at the time of treatment.
Understanding Menopause Terminology
It’s crucial to differentiate between various menopause-related terms:
Menopause and Climacteric: Menopause refers to the last menstrual period. Climacteric more accurately describes the gradual changes and symptoms that occur as hormone production and ovarian function decline. The process of periods stopping is usually gradual and akin to puberty.
Premenopause: This stage refers to when periods are still regular, but initial symptoms like night sweats and mood swings may appear. However, it can also mean the years when periods are regular and fertility is present. Context is crucial to understanding the intended meaning.
Perimenopause: POI should not be confused with perimenopause. Perimenopause lasts several years before and after the last menstrual period. Symptoms that may have seemed insignificant become meaningful when viewed as part of perimenopause. This is when physical changes are most noticeable, with irregular periods and hot flashes. During this stage, fertility remains, although pregnancy chances are often negligible. Perimenopause is characterized by changing ovarian hormones and reduced egg production, with rising Follicle Stimulating Hormone levels as a key indicator.
Post-menopause: This term describes the time from the last menstrual period to the end of life.
Hormones and POI
Estrogen: Estrogen is the primary female sex hormone produced by the ovaries, essential for egg development and reproduction. It also plays a vital role in maintaining cardiovascular, brain, and bone health.
Progesterone: Progesterone, also produced by the ovaries, helps maintain pregnancy. It signals to the uterus that an egg has been released.
Follicle Stimulating Hormone (FSH): FSH, released by the pituitary gland, stimulates the follicles in the ovaries. As FSH levels rise, some eggs respond with low levels of estrogen, signaling to the pituitary gland that the follicles have been stimulated, slowing FSH production. When the supply of egg follicles is low and unresponsive to stimulation, the pituitary gland produces more FSH each month, resulting in overall increased FSH levels. POI is suspected if you are under 40, have infrequent or absent periods, and your FSH level exceeds 30 iu/l. A single FSH level test is not conclusive, and levels should be repeated in 4-6 weeks to confirm the diagnosis.
Luteinizing Hormone (LH): LH, released by the pituitary gland, triggers ovulation, causing the active follicle to release the egg. The ruptured follicle sac, called the corpus luteum, produces progesterone. LH is also elevated in POI, but usually less so than FSH.
Testosterone: Although primarily considered a male hormone, testosterone is vital for women. It plays a role in libido, sexual health, bone strength, and energy. About half of a woman’s testosterone is produced by the ovaries, with the other half from the adrenal gland. Testosterone levels decrease with age but can drop by 50% after surgical removal of the ovaries. Women with POI have lower testosterone levels compared to other women of the same age.
Conclusion
Understanding what POI is, its causes, and how it differs from typical menopause is crucial for those affected by this condition. Recognizing the role of hormones and the various factors contributing to POI can aid in diagnosis and management. Early diagnosis and appropriate management can help mitigate the effects of POI on women’s health and well-being.
