During a girls cycle an unfertilized egg sheds on the uterine wall. This mainly lasts for about 7 days. When a unfertilized egg reaches the unterine wall it tens to shed which makes it a cycle.
A girls menstrual cycle is an unfertilized egg sheds on the uterine wall. This lasts for about 5-7 days. When a unfertilized egg reaches the unterine wall it tends to shed which makes it a cycle. This happens every month unless pregnant. It doesnt happen when pregnant due to the egg being used not needing to be released to the uterine wall.