Mechanism of action of oral contraceptive pill can be all except ?
Hostile to sperm penetration
Anovulatory cycle
Failure of blastocyst implantation
Blockade of fimbrial ostia
Ans. is 'd' i.e., Blockade of fimbrial ostia Mechanism of action of OCPs 1nihibition of gonadotropin release from pitutary by reinforcement of normal feedback inhibition - No prevulatory LH surge - No ovulation This is the most impoant mechanism. Thickening of cervical mucus secretion (due to progesterone) - hostile to sperm penetration. Even if ovulation and feilization occur, the blastocyte fails to implant because endometrium is either hyperproliferative or hypersecretory - not suitable for nidation - Impoant in case of postcoital pill. Uterine and tubal contractions may be modified to disour feilization. Postcoital pills may dislodge a just implated blastocyte or may interfere feilization/implantation.