Primary ovarian insufficiency
Primary ovarian insufficiency, also called premature ovarian insufficiency and premature ovarian failure, is the partial or total loss of reproductive and hormonal function of the ovaries before age 40 because of follicular dysfunction or early loss of eggs. POI can be seen as part of a continuum of changes leading to menopause that differ from age-appropriate menopause in the age of onset, degree of symptoms, and sporadic return to normal ovarian function. POI affects approximately 1 in 10,000 women under age 20, 1 in 1,000 women under age 30, and 1 in 100 of those under age 40. A medical triad for the diagnosis is amenorrhea, hypergonadotropism, and hypoestrogenism.
Physical and emotional symptoms are similar to those seen during menopause and can include hot flashes, night sweats, dry skin, vaginal dryness, irregular or absent menstruation, anxiety, depression, mental fog, irritability, nervousness, decreased libido, and increased autoimmune disruption. The sense of shock and distress on being informed of the diagnosis can be overwhelming. Hormonal therapy with estrogen and progesterone is the first line treatment and is associated with improvement of symptoms and possibly improvement in other parameters such as bone density, mortality and cardiovascular risk. The general treatment is for symptoms, bone protection, and mental health. Although 5 to 10% of women with POI may ovulate sporadically and become pregnant without treatment, others may use assisted reproductive technology including in vitro fertilization and egg donation or decide to adopt or remain childless.
The causes of POI are heterogeneous and are unknown in 90% of cases. It can be associated with genetic causes, autoimmune disease, enzyme deficiency, infection, environmental factors, radiation, or surgery in 10%. Two to 5% of women with POI and a premutation in FMR1, a genetic abnormality, are at risk of having a child with fragile X syndrome, the most common cause of inherited intellectual disability.
The diagnosis is based on ages less than 40, amenorrhea, and elevated serum follicle-stimulating hormone levels. Typical serum FSH levels in POI patients is in the post-menopausal range. Treatment will vary depending on the symptoms. It can include hormone replacement therapy, fertility management, and psychosocial support, as well as annual screenings of thyroid and adrenal function.
Signs and symptoms
The signs and symptoms of POI can be seen as part of a continuum of changes leading to menopause. POI contrasts with age-appropriate menopause in the age of onset, degree of symptoms and sporadic return to normal ovarian function. As some women retain partial ovarian function, symptoms may not be as severe as regular menopause. In others, particularly with coexistent depression, symptoms such as decreased quality of life can be severe.Hormonally, POI is defined by abnormally low levels of estrogen and high levels of FSH, which demonstrate that the ovaries are no longer responding to circulating FSH by producing estrogen and developing fertile eggs. The ovaries will likely appear smaller than normal. The age of onset can be as early as 11 years. POI can be seen as part of a continuum of changes leading to menopause that differ from age-appropriate menopause in the age of onset, degree of symptoms, and sporadic return to normal ovarian function. A contrasting problem can be when a girl never begins menstruation due to a genetic condition causing primary amenorrhea.
Causes
The cause of POI is idiopathic in 39-67% of cases. Some cases of POI are attributed to autoimmune disorders such as autoimmune oophoritis, Hashimoto thyroiditis, Addison disease, type I diabetes mellitus, pernicious anemia, genetic disorders such as Turner syndrome, Trisomy X, and Fragile X syndrome, metabolic defects, and enzyme defects. One study showed a strong correlation between incidence of POI and certain variants in the inhibin alpha gene. Chemotherapy and radiation treatments for cancer can sometimes cause POI. The effect of chemotherapy or radiation is variable and in a mouse model, with results consistent with observations in humans, cyclophosphamide can result in an 87% reduction in primordial follicles 72 hours after administration. Women who have had a hysterectomy tend to go through menopause early and have a nearly twofold increased risk of POI. Almost any pelvic surgery has the potential to damage the ovary by affecting its blood supply or causing inflammation in the area resulting in POI, especially surgery to the ovaries themselves. Certain environmental toxins such as phthalates, bisphenols, and dioxins are also associated with POI. Certain infectious diseases, such as mumps or HIV may also damage the ovaries, leading to POI.Galactosemia
Women who have inherited classic galactosemia may develop primary ovarian insufficiency.Mechanism
The pathogenic mechanisms of POI are highly heterogeneous and can be divided into four major categories: follicular migration defect early in embryogenesis; an early decrease in the primordial follicles; increased follicular death; and altered maturation or recruitment of primordial follicles. These result in a decrease of the ovaries' general supply of eggs that normally lasts until an average age of 51 for age of age-appropriate menopause.Genetic causes such as Turner syndrome have initial ovarian development but then ovaries degenerate rapidly during prenatal life, often leading to gonadal dysgenesis with streak ovaries. In those cases where POI is associated with adrenal autoimmunity, histological examination almost always confirms the presence of an autoimmune oophoritis in which follicles are infiltrated by lymphocytes, plasma cells, and macrophages that attack mainly steroid-producing cells and eventually result in follicular depletion.
In some women FSH may bind to the FSH receptor site, but be inactive. By lowering the endogenous FSH levels with ethinylestradiol or with a GnRH-a the receptor sites are free and treatment with exogenous recombinant FSH activates the receptors and normal follicle growth and ovulation can occur. level is correlated with the number of remaining primordial follicles some researchers believe the above two phenotypes can be distinguished by measuring serum AMH levels.
Genetic associations include genetic disorders, autoimmune diseases, enzyme defects, and resistant ovaries.
Mutations in FOXL2 cause blepharophimosis, ptosis, epicanthus inversus syndrome. Premature ovarian failure is part of the BPES Type I variant of the syndrome but not of the BPES Type II variant.
DNA repair deficiency
protein plays an essential role in the repair of DNA double-strand breaks by homologous recombination. Women with a germline BRCA1 mutation tend to have premature menopause as evidenced by the final amenorrhea appearing at a younger age. BRCA1 mutations are associated with occult POI. Impairment of the repair of DNA double-strand breaks due to a BRCA1 defect leads to premature ovarian aging in both mice and humans.In addition to BRCA1, the MCM8-MCM9 protein complex also plays a crucial role in the recombinational repair of DNA double-strand breaks. In humans, an MCM8 mutation can give rise to premature ovarian failure, as well as chromosomal instability. MCM9, as well as MCM8, mutations are also associated with ovarian failure and chromosomal instability. The MCM8-MCM9 complex is likely required for the homologous recombinational repair of DNA double-strand breaks that are present during the pachytene stage of meiosis I. In women homozygous for MCM8 or MCM9 mutations, failure to repair breaks apparently leads to oocyte death and small or absent ovaries.
Diagnosis
The diagnosis is based on age less than forty, amenorrhea, and two elevated serum follicle-stimulating hormone and decreased estrogen measurements at one-month intervals. The anterior pituitary secretes FSH and LH at high levels to try to increase the low estrogen levels that are due to the dysfunction of the ovaries. Typical FSH in POI patients is over 40 mlU/ml. The evaluation of amenorrhea for other common causes includes checking a blood pregnancy test, checking the prolactin level, as prolactinomas or certain medications can increase prolactin levels and lead to amenorrhea, and checking the thyrotropin level, as hypothyroidism can cause amenorrhea. A karyotype and a Fragile-X premutation carrier analysis is also recommended, with additional genetic testing possibly being warranted based on family history of amenorrhea or early menopause or signs and symptoms of a genetic disorder.Treatment
Fertility
Between 5 and 10% of women with POI may become pregnant with no treatment. As of 2016, no fertility treatment has been found to effectively increase fertility in women with POI, and the use of donor eggs with in-vitro fertilization and adoption are a means of achieving parenthood for women with POI. Some women with POI choose to live child-free.Researchers have investigated the use of a hormone called dehydroepiandrosterone in women with POI to increase spontaneous pregnancy rates. Results from studies on DHEA in 2010 indicated that DHEA may increase spontaneously conceived pregnancies, decrease spontaneous miscarriage rates and improve IVF success rates in women with POI. This includes women referred for donor eggs or surrogacy in 2009. In 2018, there was no significant improvement in ovarian function by 12-month on DHEA supplementation in women with POI. Given the inconclusiveness of potential benefits and risks of testosterone and DHEA supplementation, longer-term, randomized studies are warranted for women and girls with POI.
Ovarian tissue cryopreservation can be performed on prepubertal girls at risk for premature ovarian failure, and this procedure is as feasible and safe as comparable operative procedures in children.
In 2013, Kawamura in Japan and his collaborators at Stanford University published treatment of infertility of POI patients by fragmenting ovaries followed by in vitro treatment of ovarian fragments with phosphatidylinositol-3 kinase activators to enhance the AKT pathway followed by autografting. They successfully promoted follicle growth, retrieved mature oocytes, and performed in vitro fertilization. Following embryo transfer, a healthy baby was delivered. A 2020 review covered variations including phosphatidylinositol-3 kinase activators to enhance the AKT pathway, fragmentation of ovarian cortex, combining those two into in-vitro activation, and drug-free IVA. Two laparoscopies are needed in conventional IVA and one with drug-free IVA.