A birth control pill is a hormonal form of birth control that protects against pregnancy. Because it comes in pill form, it is referred to as “the pill.” Women take the pill once a day orally (by mouth). The pill works best when taken consistently at the same time each day.1 However, the pill does not provide protection against sexually transmitted infections such as HIV. Most STIs are best protected by using a latex condom when having sexual intercourse or even oral sex.2
Overview:
- The birth control pill works by preventing the interaction of sperm and egg. Fertilization occurs when sperm and an egg combine.
- The hormones in the pill stop ovulation safely. Because there is no egg for sperm to fertilize, pregnancy is not possible.
- The hormones in the pill thicken the mucus on the cervix as well. This thicker cervical mucus acts as a sticky security guard, preventing sperm from swimming to an egg.3
How do birth control pills work?
Pregnancy occurs when sperm fertilizes an egg released by your ovary (the organ that holds eggs). The fertilized egg attaches to the wall of the uterus where it grows into a baby. Hormones in your body control the release of the egg from the ovary, known as ovulation, and prepare your body to receive the fertilized egg.
Hormonal contraceptives (the pill, patch, and vaginal ring) all include small traces of human-made hormones – estrogen and progestin. These hormones interfere with your body’s natural hormones in a variety of ways to prevent conception. The hormonal contraceptive prevents the body from ovulating in most cases. They also alter the cervical mucus to make it more difficult for sperm to pass through and discover an egg. They can also prevent pregnancy by altering the womb’s lining and making it thick and less likely for the fertilized egg to be implanted.4
How do the two types of birth control pills work?
1. Combination pills or COCPs:
Combination pills have two functions. The first is to stop your body from ovulating. This indicates that your ovaries will not produce an egg every month. Second, these pills make your cervical mucus thicker, which prevents the sperm from traveling to your uterus and fertilizing an egg. The thick mucus prevents the sperm from entering the uterus.
2. Progestin-only pills or POPs or mini-pills:
Progestin-only pills function in a variety of ways. They primarily work by thickening cervical mucus and thinning the endometrium. The endometrium is the uterine lining where an egg implants following fertilization. If this lining is thinner, it will be more difficult for an egg to implant, preventing pregnancy from occurring. Ovulation may also be prevented by progestin-only pills.
How can you make the pill most effective to work for you?
When used properly, the birth control pills are 99% effective at preventing pregnancy. But since people are not perfect and it’s easy to forget or miss the pill, it is 91% effective in reality.5 This means that the pill has a 9% failure rate even when taken regularly. In other words, 9 out of every 100 women who use the pill have a chance of getting pregnant.
Progestin pills must be taken at the same time every day for them to be fully effective. If you miss this window, take your pill as soon as you remember and utilize another means of contraception for two days, such as a condom.
Combination pills provide a little more freedom. In general, you should take combination pills at the same time each day, but you can take them anytime within a 12-hour window and still be protected from pregnancy.5
