( A ) Ovulation - LH and FSH attain peak level and sharp fall in the secretion of progesterone
( B ) Proliferative phase - Rapid regeneration of myometrium and maturation of Grafian follicle
( C ) Menstruation - Breakdown of myometrium and ovum not fertilized
( D ) Development of corpus luteum - Secretory phase and increased secretion of progesterone
