anovulatory menstruation
menstruation
[men″stroo-a´shun]Menstruation usually starts between the ages of 11 and 14 and continues into the forties or fifties. At first the periods may be irregular, but once they are established they usually occur in a fairly definite rhythm, at intervals of 21 to 35 days. In these regular cycles, there may be monthly variations of a few days, which are considered normal. Cycle length may be influenced by changes in climate or living conditions, or by emotional factors. Slight irregularities, especially if they occur over a period of time, may be warnings of disturbance of either the thyroid or pituitary glands, or of tumors of the uterus or ovaries.
Occasionally menstruation does not occur at puberty; this is known as primary amenorrhea. It may be caused by underdevelopment or malformation of the reproductive organs, or by glandular disturbances, which generally can be corrected by the administration of hormones.
General ill health, a change in climate or living conditions, emotional shock, or, frequently, either the hope or fear of becoming pregnant can sometimes stop menstruation after it has begun (secondary amenorrhea). If this cessation is of short duration, it is not a cause for alarm. If it continues over a long period of time, and there is also the problem of infertility, hormone treatments may be necessary.