Changes

* The corpus luteum reaches full size at 4-5 days after ovulation but does not protrude from the ovarian surface.

* The corpus luteum reaches full size at 4-5 days after ovulation but does not protrude from the ovarian surface.

* On section of the ovary, the corpus luteum will appear brown and later yellow.  It is triangular or conical in shape, with the narrow end on the ovulaiton fossa.  The centre of the corpus luteum normally contains dark brown fibrin.

* On section of the ovary, the corpus luteum will appear brown and later yellow.  It is triangular or conical in shape, with the narrow end on the ovulaiton fossa.  The centre of the corpus luteum normally contains dark brown fibrin.

* The corpus luteum of the cycle (non-pregnant) starts to regress on about the 12th day of the cycle.  At the time of regression, there is a fall in blood progesterone concentration.

* The corpus luteum of the cycle (non-pregnant) starts to regress on about the 12th day of the cycle.  At the time of [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology#Corpus_Luteum_Regression|regression]], there is a fall in blood progesterone concentration.