Birth Control pill
Key points
- The birth control pill is a daily pill that contains the hormones estrogen and progesterone that prevent pregnancy (also called the Pill).
- Most birth control pills contain the combination of the hormones estrogen and progesterone to prevent ovulation (the release of an egg during the monthly cycle).
- Over the course of one year about five out of 100 typical couples who rely on the Pill to prevent pregnancy will have an accidental pregnancy.
- The birth control pill does not protect against sexually transmitted diseases (STDs).
What Is It?
The birth control pill is a daily pill that contains the hormones estrogen and progesterone that prevent pregnancy (also called the Pill).
How Does It Work?
Most birth control pills contain the combination of the hormones estrogen and progesterone to prevent ovulation (the release of an egg during the monthly cycle). If a woman doesn't ovulate she cannot get pregnant because there is no egg to be fertilized.
One type of birth control pill, known as the Minipill, contains only the hormone progesterone. Although progesterone alone may prevent ovulation, this may not occur reliably every month. The Minipill also works by thickening the mucous around the cervix, which prevents the sperm from entering the uterus. It also affects the lining of the uterus so if the egg is fertilized it cannot attach to the wall of the uterus.
The combination pill comes in either a 21-day pack or a 28-day pack. One hormone pill is taken each day at about the same time for 21 days. Depending on your pack, you will stop taking pills for 7 days or you will take a reminder pill (that contains no hormones) for 7 days. A woman has her period when she stops taking the pills with hormones. Some women prefer the 28-day pack because it helps them stay in the habit of taking a pill every day.
The Minipill is taken every day - there are no reminder pills. On the Minipill you may have no period or you may go several months without a period, which means you are not ovulating. If you are having regular periods, you are probably still ovulating and are at greater risk of getting pregnant.
The Pill works best when it is taken every single day at the same time of day, regardless of whether you are going to have sex. This is especially important with progesterone-only pills. You should not take a friend's or sister's pills. If pills are skipped or forgotten, you are not protected against pregnancy and backup birth control, such as condoms, must be used.
How Well Does It Work?
Over the course of one year about five out of 100 typical couples who rely on the Pill to prevent pregnancy will have an accidental pregnancy. Of course, this is an average figure and the chance of getting pregnant depends on whether you take your birth control pills every day. The Pill is an effective form of birth control, but even missing 1 day increases the chance of getting pregnant.
In general, how well each type of birth control method works depends on a lot of things. These include whether a person has any health conditions or is taking any medications that might interfere with its use. It also depends on whether the method chosen is convenient - and whether the person remembers to use it correctly all the time.
Protection Against STDs?
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.