They work by introducing synthetic hormones into the body to mimic the natural hormones involved in the menstrual cycle. There are two main types of oral contraceptives: combination pills and progestin-only pills.
Combination Pills: Combination pills contain two types of hormones: estrogen and progestin. The two main ways combination pills work are:
a. Inhibition of Ovulation: The hormones in the combination pill prevent the release of an egg (ovulation) from the ovaries. Without a released egg, there is no egg available for fertilization by sperm, reducing the chances of pregnancy.
b. Thinning of Uterine Lining: The hormones also cause the uterine lining to become thinner. This makes it less likely for a fertilized egg to implant and grow in the uterus.
Progestin-Only Pills: Progestin-only pills (also called mini-pills) contain only progestin, without any estrogen. These pills primarily work by:
a. Thickening Cervical Mucus: Progestin thickens the cervical mucus, making it difficult for sperm to reach and fertilize an egg.
b. Inhibition of Ovulation: Like combination pills, progestin-only pills can also inhibit ovulation, although they may not do so consistently in every cycle.
It’s important to note that oral contraceptives are most effective when taken consistently and correctly. It’s typically recommended to take them at the same time each day to maintain their effectiveness. While oral contraceptives are highly effective, they do not protect against sexually transmitted infections (STIs). Therefore, using condoms or other barrier methods in addition to oral contraceptives is advisable if you want to protect against both pregnancy and STIs.