The absence of menstrual periods is known as

Amenorrhoea simply means an absence of your periods. Doctors usually classify amenorrhoea into primary or secondary amenorrhoea. Girls who haven't started their periods by the time they're 16 years old or 3 years after they've shown the first signs of puberty have primary amenorrhea, which is usually caused by a genetic abnormality, a hormone imbalance, or a structural problem.