What is the effect of Progesterone-only pills?

Ref. KDT. Page. 343 Progestogen-only pills have multiple biological effects on the female body. Multitude effect of POP: Inhibition of follicular development Inhibition of ovulation Suppression of corpus luteum formation Changes in the nature of the cervical mucus which inhibits the passage of sperms into the uterine cavity – Thickening of cervical mucous secretion Effects on the endometrium which affect implantation – by making it thin