Amenorrhea Amenorrhea is the absence of menstruation. There are two types of amenorrhea, primary and secondary. Primary amenorrhea is delayed menarche (the first menstrual period) and is defined as any one of three conditions: 1.) absence of menarche by...

(US: amenorrhea) Absence or failure of menstruation (see MENSTRUAL CYCLE). The menstrual cycle is typically, in humans, a 28-day period, though there is considerable individual variation in this. Absolute loss of menstruation can occur for a variety of...

Amenorrhoea (BE), amenorrhea (AmE), or amenorrhœa, is the absence of a menstrual period in a woman of reproductive age. Physiologic states of amenorrhoea are seen during pregnancy and lactation (breastfeeding), the latter also forming the basis of a...