Corpus luteum functions maximally without an implantaton for ...... days :

9 days After ovulation the ruptured graffian follicle develops into corpus luteum. The lile cycle ot corpus luteum has four stages viz : Proliferation Vascularisation Maturation Begression Corpus luteum reaches it maximum maturity by 22nd day of cycle (gze = 2 cms or more). Ovulation occurs on day 14 i.e. 8th days atter ovulation corpus luteum reaches its maximum maturity. Colour of corpus luteum in early stages is greyish yellowdeg due to presence of lipids and later is distinctive yellow due to pigment carotene.deg lf pregnancy does not occur corpus luteum stas degenerating from the eight post ovulatory day and forms coruous albicans. lf pregnancy occurs, HCG similar lo LH stimulates corpus luteum to secrete progesterone. it's groMh roaches a peak at 8th week ol gestation and it remains functionally active till 10-12 weeks of geNation, where by placenta takes over its lunction of producing progesterone. This is followed by degenerative changes in corpus luteum.