The Mechanism: How the Pill Prevents Pregnancy
The birth control pill, also called the oral contraceptive pill, is a highly effective method of preventing pregnancy. The pill works by disrupting the normal menstrual cycle and preventing the ovulation of an egg. Each pill contains synthetic hormones that mimic the effects of progesterone and estrogen, two hormones that regulate the menstrual cycle. These hormones act together to prevent pregnancy in three different ways.
Preventing Ovulation
The primary function of the birth control pill is to prevent ovulation. Ovulation is the process by which an egg is released from the ovary and travels down the fallopian tube, where it may potentially be fertilized by a sperm. The pill contains hormones that prevent the release of an egg from the ovary, making it impossible for sperm to fertilize an egg. This is the most effective method of preventing pregnancy, with a failure rate of less than 1% when used correctly.
Thickening Cervical Mucus
The hormones in the pill thicken the cervical mucus, making it more difficult for sperm to reach the egg. The cervical mucus normally changes in consistency and volume throughout the menstrual cycle, becoming thin and clear around the time of ovulation. By thickening the mucus, the pill creates a physical barrier that prevents sperm from reaching the egg. This method is not as effective as preventing ovulation, but it provides an extra layer of protection against pregnancy.
Thin Uterine Lining
The hormones in the pill also thin the lining of the uterus, which makes implantation of a fertilized egg less likely. Normally, after an egg has been fertilized, it will continue to travel down the fallopian tube and implant in the lining of the uterus. By thinning the lining, the pill prevents the fertilized egg from implanting, thus preventing pregnancy. This method is also not as effective as preventing ovulation, but it provides another barrier against pregnancy.
The Importance of Consistency
The effectiveness of the birth control pill depends on consistent use. Missing even one pill can increase the risk of ovulation and decrease the effectiveness of the pill. It is important to take the pill at the same time every day and use backup methods of contraception, such as condoms, if a pill is missed or taken late. The pill does not protect against sexually transmitted infections (STIs), so using a condom in addition to the pill is important for preventing STIs.
