Definition

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

• the absence of menarche by age 16 in a girl with otherwise normal pubertal development (development of breasts and/or pubic hair)
• the absence of menarche by age 14 combined with delayed pubertal development
• the absence of menarche two years after puberty is otherwise completed

Secondary amenorrhea is defined as the absence of menstruation after menarche has taken place. Although it is not uncommon for a girl's menstrual...