Amenorrhea

Amenorrhea is defined as the absence of menstruation, which is the vaginal bleeding that forms part of the menstrual cycle and prepares the female body for pregnancy.

There are two types of amenorrhea:

• Primary amenorrhea: absence of the first menstrual period (menarche) by age 15 in adolescents who have developed secondary sexual characteristics and show a normal growth pattern. If amenorrhea is accompanied by absent breast development, it is considered pathological at age 13.
• Secondary amenorrhea: absence of menstruation for 3 months in women with previously regular cycles, or for 6 months in those with irregular cycles.

Amenorrhea may be indicative of pregnancy, a reproductive tract abnormality, or an underlying general health disorder. Therefore, identifying the cause is essential in order to establish the most appropriate treatment in each case.

Symptoms

The hallmark symptom of amenorrhea is the absence of menstrual periods. Depending on the underlying cause, it may be associated with other symptoms, such as:

• Changes in breast size
• Nipple discharge (galactorrhea)
• Weight gain or weight loss
• Vaginal dryness
• Headache
• Hair loss
• Excess facial hair
• Acne
• Pelvic pain
• Visual disturbances

Causes

The absence of menstruation may result from a wide variety of causes. The most relevant include:

• Physiological amenorrhea: part of the normal changes in a woman’s body throughout life:
• Pregnancy: increased levels of human chorionic gonadotropin (hCG)
• Lactation: elevated prolactin levels required for milk production usually inhibit menstruation
• Menopause: gradual decline in hormone levels and reproductive capacity over time
• Primary amenorrhea:
• Gonadal dysgenesis: a genetic condition affecting ovarian development during embryogenesis, often resulting in ovarian insufficiency and absence of menstruation
• Congenital anomalies of the reproductive system: incomplete or abnormal formation of reproductive organs:
• Müllerian agenesis: absence of the uterus and part of the vagina
• Cervical agenesis: absence of the cervix
• Uterine agenesis: absence of the uterus
• Imperforate hymen, leading to accumulation of menstrual blood in the vagina
• Transverse vaginal septum: presence of a membrane dividing the vagina and preventing menstrual flow
• Turner syndrome: complete or partial absence of one X chromosome, resulting in premature ovarian failure
• Uterine hypoplasia: underdevelopment of the uterus, with a length of less than 5–7 cm
• Pituitary tumors: neoplasms of the gland responsible for synthesizing, storing, and secreting hormones involved in sexual development and reproduction, often disrupting menstrual cycles
• Secondary amenorrhea:
• Acquired reproductive tract abnormalities:
• Asherman syndrome: intrauterine adhesions or scar tissue that reduce menstrual flow or cause complete absence of menstruation, often related to procedures such as cesarean section, curettage, or pelvic radiotherapy
• Cervical stenosis: narrowing of the cervical canal due to postmenopausal changes, surgical procedures, or radiotherapy
• Reproductive tract infections
• Trauma
• Functional hypothalamic amenorrhea: a condition in which inadequate activation of the hypothalamic–pituitary–ovarian axis leads to temporary suppression of reproductive function, due to causes such as:
• Low body weight: ovulation may cease when body weight is approximately 10% below normal
• Psychological stress: alters hypothalamic regulation of the menstrual cycle
• Excessive exercise: often associated with low body weight, high energy expenditure, and competitive stress
• Polycystic ovary syndrome (PCOS): elevated androgen levels prevent ovulation, leading to chronic anovulation and irregular or absent menstruation
• Hyperprolactinemia: increased prolactin levels inhibit gonadotropin-releasing hormone (GnRH) secretion and reduce follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, resulting in anovulation
• Thyroid disorders: thyroid hormones play a significant role in the menstrual cycle; both excessive production (hyperthyroidism) and deficient production (hypothyroidism) may cause anovulation
• Hormonal contraceptives: a common side effect is the absence of menstruation
• Certain medications: antidepressants, antipsychotics, anticonvulsants, calcium channel blockers, anabolic steroids, and oncological treatments are frequently associated with amenorrhea
• Pituitary tumors

Risk Factors

Factors that increase the risk of amenorrhea include:

• Family history, as many conditions causing amenorrhea have a genetic basis
• Eating disorders and low body weight
• High-performance athletic training
• Previous gynecological procedures, such as cesarean sections, curettage, or uterine biopsies
• Presence of diseases or use of medications associated with absence of menstruation

Complications

The most frequent complications of amenorrhea include:

• Infertility: absence of ovulation prevents conception
• Spontaneous miscarriage resulting from hormonal imbalances
• Osteoporosis: low estrogen levels contribute to decreased bone density
• Cardiovascular disease: estrogens protect blood vessels and cardiac function; deficiency may impair cardiovascular health

Which specialist treats amenorrhea?

Amenorrhea may be managed within the specialties of Gynecology and Obstetrics or Endocrinology and Nutrition.