Absence of menstruation, i.e. either lack of menarche or cessation of menses
Amenorrhea can be of three types:
Where menstruation has never happened. Usually primary amenorrhea implies that menstruation has not started by the age of 16. However competent diagnosis is called for as are a number of diverse causes to consider, including imperforate hymen, ovarian dysfunction or hormonal imbalance.
when menstruation stops after at least one period. This is a common occurrence with causes including pregnancy, stress, loss or gain of weight, menopause, breast-feeding, anemia, excessive exercise, stopping contraceptive pill intake, some drugs, ovarian cysts or tumors etc.
Irregular or erratic menstruation
There may be 3 or 4 periods in an year,or 3 close together followed by none for a few months. Causes are same as secondary amenorrhea.