How do birth control pills work to prevent pregnancy?

Hormones: Birth control pills contain hormones that suppress the cycle that leads to ovulation. They also alter the cervical mucous, making it more difficult for sperm to get through.

BCP: Works in three ways, 1- by inhibiting ovulation, 2-by creating a very thin lining(endometrium), making it difficult for a fertilized egg to implant in the uterus, 3-creates a hostile cervical mucus that doesn't allow the sperms to undergo capacitation and swim freely upstream. Also decreases to motility of the tubes making it difficult for sperm and egg to get together.