Pills:
I. Inhibit ovulation and implantation
II. Alter the quality of cervical mucus to prevent or retard the entry of sperms
III. Prevent the ejaculated semen from entering the female vagina
IV. Inhibit spermatogenesis
Pills inhibit ovulation and implantation as well as alter the quality of cervical mucus to prevent/ retard entry of sperms. Pills are very effective with lesser side effects and are well accepted by the females. (page-61)