(a) Ovarian event from 13-15 days of one set of menstrual cycle, a mature red ovum (egg cell) is released. Ovum covered by a number of layer and a yellow fat layer forms corpus leutum. It releases (secretes) progesterone.
(b) Ovarian hormone level from 16 to 13 days that is called luteal phase (Secretory Phase) The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium.
(c) Uterine events from 24 ot 29 days are under the influence of progesterone. This leads to the maintenance of the endometrium for any pregnancy to occur. In the absence of pregnancy the endometrium is shed off.