What is primary amenorrhea?

No period by age 16: Primary amenorrhea describes a situation in which a girl does not have her first period by age 16. This may or may not be associated with lack of physical changes such as a growth spurt, hair growth in the pubic and underarm areas, and breast development.

Thanks for asking!: Menarche [ menstrual cycle] is one of the latest signs of puberty .Primary amenorrhea is absence of menarche with normal pubertal development.

Never had a period: If your brain isn't signalling for an egg release from your ovary, you won't have a signal for your periods either; that's usually the cause of amenorrhea. Often it's a hormonal imbalance--Thyroid, Prolactin, LH, FSH, Hcg should be checked. Your doctor can also induce a period as well w/ OCPs. If you've NEVER had a period, you should get an US to make sure you have normal uterus/vagina/ovaries.