Oral contraceptives (also known as birth control pills or BCPs) are used to prevent pregnancy. Taken properly, they are about 99 percent effective in preventing pregnancy. They are even more effective when used in combination with other birth-control methods, such as condoms.
There are many different brands of birth control pills. Most contain a combination of the two female hormones estrogen and progesterone, but there are some BCPs that only contain progesterone. These different brands may need to be taken in slightly different ways and may have different benefits and risks, but whichever type you use, it’s very important to take them properly to get the most benefit.
You cannot take a birth control pill only when you remember to or just after you’ve had a sexual encounter — they must be taken daily.
First of all, it’s important to know which oral contraceptive you are taking. These pills usually come in packs of 21, 28, or 91 tablets and need to be taken daily.
- Packs of 21: Take one pill each day until all 21 are gone, then don’t take a pill for seven days – this is when you should have your period. After seven days off, start a new pack of 21 pills.
- Packs of 28: Take one pill each day, and when you finish with the pack start a new pack the next day. Sometimes these packs have pills with different colors that contain different doses of the hormones or inactive ingredients, vitamins, or minerals. They must be taken in order.
- Packs of 91: The 91-tablet pack is larger and may contain three trays – take one pill each day until all 91 pills have been taken and then start the new pack of 91 pills the next day.
When you first receive a prescription for birth control pills, you will start taking the pills on the first or fifth day of your period or on the first Sunday after you have started bleeding. It’s important to discuss this with a health-care provider so that you know when to take your first pill. Also, the pill will not be immediately effective in preventing pregnancy – it must be taken daily for at least a week or more before you are fully protected, so you will need to use a backup method such as condoms until the pills take full effect.
You need to take one pill each day at the same time – or as close to the same time as you can. Taking the pill with food cuts down on nausea and stomach upset, so if you experience these side effects you can coordinate a regular meal with taking your pill – additionally, if you eat regular meals, this may help you to take the pill at the same time every day. If you do not take oral contraceptives regularly as prescribed, you have a greater chance of getting pregnant. You cannot take a birth control pill only when you remember to or just after you’ve had a sexual encounter. They don’t work like Plan B!
If you miss taking a pill, you may not be protected from pregnancy. You may need to use a backup method depending on when you missed a pill or how many pills you have missed. Additionally, this means that you must start each new pack of pills on time. Also, if you vomit or have diarrhea, you may not be protected from pregnancy. Each brand of pills has an informational sheet with directions to guide you if you miss taking a pill. Follow the instructions for your brand of pill. It’s a good idea to keep one of these informational inserts handy so that you can refer to it for other information such as side effects and when you should call a health care provider.
Birth control pills can have side effects, so it’s important to discuss these with a health care provider before you decide which type of contraception to use. Some side effects can be serious and it’s important to see a doctor if you develop them, so always refer back to the manufacturer’s information or call a doctor if you are unsure about a side effect.
Additionally, BCPs may interact with other medications, so let the pharmacist or doctor know everything you are taking, including vitamins and herbs. For example, some antibiotics may make the birth control pill less effective and you may need to use a backup method while you are on the antibiotic.
Three more points to keep in mind when you are using oral contraceptives:
- You should not smoke when you take the pill because it can increase your risk for heart attacks or strokes.
- Birth control pills do not protect you against sexually transmitted infections, so it may be necessary to use a barrier method, such as a condom or dental dam.
- Remember to check the expiration date on the packet of pills if you have enough to last several months so that you aren’t using an expired packet of pills.
Planned Parenthood can provide you with more information about birth control pills and other contraceptive choices. You can make an appointment at a Planned Parenthood health center to discuss your options with a clinician.