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Menstrual Disorders

The median age of menarche is 12.8 years, and the normal menstrual cycle is 21 to 35 days in length. Bleeding normally lasts for 3 to 7 days and consists of 30 to 40 mL of blood. Cycles are abnormal if they are longer than 8 to 10 days in duration or if more than 80 mL of blood loss occurs. Soaking more than 25 pads or 30 tampons during a menstrual period is usually abnormal.


Regular ovulatory menstrual cycles often do not develop until 1 to 1.5 years after menarche, and 55-82% of cycles are anovulatory for the first 2 years after menarche.

Adolescents frequently experience irregular menstrual bleeding patterns, which can include several consecutive months of amenorrhea.

The Normal Menstrual Cycle

During the follicular phase, release of gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the pituitary to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which then stimulate ovarian estrogen secretion, which induces endometrial proliferation. As estrogen levels peak, the pituitary gland releases increased amounts of LH.

Ovulation occurs 12 hours after the midcycle surge in LH.

The luteal phase follows ovulation, and the corpus luteum secretes progesterone and estrogen. Progesterone inhibits endometrial proliferation and induces glandular changes. Without fertilization, the corpus luteum regresses, resulting in a decrease in progesterone and estradiol, and sloughing of the endometrium 14 days after ovulation amenorea.


Primary amenorrhea is defined as the absence of menarche by age 16. Puberty is considered delayed and warrants evaluation if breast development (the initial sign of puberty in girls) does not begin by the age of abnormal vaginal bleeding, dysfunctional uterine bleeding 13. The meantime between the onset of breast development and menarche is 2 years. Absence of menses within 2 to 2.5 years of the onset.

Secondary amenorrhea is defined as the absence of 3 consecutive menstrual cycles or 6 months of amenorrhea in patients who have already established regular menstrual periods.

Differential Diagnosis of Amenorrhea


Hormonal Contraception

Hypothalamic-related Disorders

      Chronic or systemic illness



      Eating disorders




Pituitary-related Disorders





Ovarian-related Disorders



      Ovarian failure

      Resistant ovary

Outflow Tract-related Disorders

      Imperforate hymen

      Transverse vaginal septum

      Agenesis of the vagina, cervix, uterus

      Uterine synechiae

Androgen Excess

      Polycystic ovarian syndrome

      Adrenal tumor

      Adrenal hyperplasia (classic and nonclassic)

      Ovarian tumor

Other Endocrine Disorders

      Thyroid disease

      Cushing syndrome

Amenorrhea with Pubertal Delay

Hypergonadotropic hypogonadism is caused by ovarian failure associated with elevated gonadotropin levels. An elevated FSH will establish this diagnosis.

Turner syndrome (XO) may cause ovarian failure and a lack of pubertal development. Females with Turner syndrome have streak gonads, absence of one of the X chromosomes, and inadequate levels of estradiol. They do not initiate puberty or uterine development. This syndrome is characterized by short stature, webbed neck, widely spaced nipples, shield chest, high arched palate, congenital heart disease, renal anomalies, and autoimmune disorders (thyroiditis, Addison disease). It may not be diagnosed until adolescence, when pubertal delay and amenorrhea occur together.

Ovarian failure resulting from autoimmune disorders or exposure to radiation or chemotherapy may also cause amenorrhea with pubertal delay associated with hypergonadotropic hypogonadism.

Hypogonadotropic Hypogonadism is caused by hypothalamic dysfunction or pituitary failure. Low or normal levels of LH and FSH will be present, and decreased estradiol levels may be present.

Abnormalities of the pituitary and hypothalamus, and other endocrinopathies (thyroid disease and Cushing syndrome) may present with pubertal delay and low gonadotropin levels.

Amenorrhea may be caused by problems at the level of the pituitary gland, such as congenital hypopituitarism, tumor (pituitary adenoma), or infiltration (hemochromatosis).

Prolactin-secreting pituitary adenoma (prolactinoma) is the most common pituitary tumor. Prolactinomas present with galactorrhea, headache, visual fields cuts, and amenorrhea. Elevated prolactin levels are characteristic; galactorrhea is not always present. Tumors smaller than 1 cm may present only with galactorrhea and amenorrhea.

Craniopharyngioma is another tumor of the sella turcica that affects hypothalamic-pituitary function, presenting with pubertal delay and amenorrhea.

Other disorders associated with galactorrhea and amenorrhea include hypothyroidism, breast stimulation, stress associated with trauma or surgery, and certain drugs (phenothiazines, opiates).

Hypothalamic suppression is most commonly caused by stress, competitive athletics, and inadequate nutrition (anorexia nervosa).

Hypothalamic abnormalities associated with pubertal delay include Laurence-Moon-Biedl, Prader-Willi, and Kallmann syndromes. Laurence-Moon-Biedl and Prader-Willi present with obesity. Kallmann syndrome is associated with anosmia.

Amenorrhea with Normal Pubertal Development

When amenorrhea occurs in a pubertally mature females, pregnancy should be excluded.

Contraceptive-related amenorrhea occurs with depot medroxyprogesterone (Depo-Provera) and levonorgestrel implants (Norplant); it does not require intervention; however, a pregnancy test should be completed.

Uterine synechiae (Asherman syndrome) should be suspected in amenorrheic females with a history of abortion, dilation and curettage, or endometritis.

Sheehan syndrome (pituitary infarction) is suggested by a history of intrapartum bleeding and hypotension.

Other Disorders Associated with Amenorrhea and Normal Pubertal Development. Ovarian failure, acquired abnormalities of the pituitary gland (prolactinoma), thyroid disease, and stress, athletics, and eating disorders may cause amenorrhea after normal pubertal development has occurred. Polycystic ovarian disease, which is usually associated with irregular bleeding, can also present with amenorrhea.

E. Genital Tract Abnormalities

1. Imperforate hymen will appear as a membrane covering the vaginal opening. A history of cyclic abdominal pain is common, and a midline abdominal mass may be palpable.

2. Transverse vaginal septum may cause obstruction. It is diagnosed by speculum examination.

3. Agenesis of the vagina appears as a blind-ended pouch. Normal pubertal development of breast and pubic hair occurs, but menarche does not occur.

4. Androgen insensitivity (testicular feminization syndrome) is another common cause of vaginal agenesis.