Primary amenorrhea

Amenorrhoea
Classification and external resources
Specialty	Gynecology
ICD-10	N91.0-N91.2
ICD-9-CM	626.0
DiseasesDB	14843
MedlinePlus	001218 (primary) 001219 (secondary)
eMedicine	article/953850
Patient UK	Amenorrhea
MeSH	D000568
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Amenorrhoea (BE), amenorrhea (AmE), or amenorrhœa, is the absence of a menstrual period in a woman of reproductive age. Physiological states of amenorrhoea are seen, most commonly, during pregnancy and lactation (breastfeeding), the latter also forming the basis of a form of contraception known as the lactational amenorrhoea method. Outside of the reproductive years there is absence of menses during childhood and after menopause.

Amenorrhoea is a symptom with many potential causes. Primary amenorrhoea (menstrual cycles never starting) may be caused by developmental problems, such as the congenital absence of the uterus or failure of the ovary to receive or maintain egg cells. Also, delay in pubertal development will lead to primary amenorrhoea. It is defined as an absence of secondary sexual characteristics by age 14 with no menarche or normal secondary sexual characteristics but no menarche by 16 years of age. Secondary amenorrhoea (menstrual cycles ceasing) is often caused by hormonal disturbances from the hypothalamus and the pituitary gland, from premature menopause or intrauterine scar formation. It is defined as the absence of menses for three months in a woman with previously normal menstruation or nine months for women with a history of oligomenorrhoea.

There are two primary ways to classify amenorrhoea. Types of amenorrhoea are classified as primary or secondary, or based on functional "compartments". The latter classification relates to the hormonal state of the patient that hypo-, eu-, or hypergonadotropic (whereby interruption to the communication between gonads and follicle stimulating hormone (FSH) causes FSH levels to be either low, normal or high).

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