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Definition
Combination birth control pills, also known as the pill, are oral contraceptives that contain estrogen and a progestin.
Combination birth control pills suppress ovulation — keeping your ovaries from releasing an egg. Combination birth control pills also thicken cervical mucus and thin the lining of the uterus (endometrium) to keep sperm from reaching the egg.
Different types of combination birth control pills contain different doses of estrogen and progestin. Other types of combination birth control pills allow you to reduce the number of periods you have each year. If you'd like to use combination birth control pills, your health care provider can help you decide which type is right for you. For maximum effectiveness, you must take combination birth control pills at the same time every day.
Why it's done
Combination birth control pills are a common type of contraception. Benefits of combination birth control pills may include:
- A decreased risk of ovarian and endometrial cancers, ectopic pregnancy, ovarian cysts, uterine fibroids, benign breast disease and iron deficiency anemia
- Less severe menstrual cramps (dysmenorrhea)
- Relief from premenstrual syndrome (PMS)
- Shorter, lighter and more predictable periods or, for some types of combination pills, fewer periods each year
- An improvement in acne
- A reduction in androgen production caused by polycystic ovary syndrome
- A possible decreased risk of postmenopausal hip fracture
Combination birth control pills come in different mixtures of active and inactive pills, including:
- Conventional pack. The most common type of combination birth control pills contains 21 active pills and seven inactive pills. Formulations containing 24 active pills and four inactive pills, known as a shortened pill-free interval, also are available. Bleeding occurs every month during the week when you take the last four to seven inactive pills.
- Continuous dosing or extended cycle. These combination birth control pills typically contain 84 active pills and seven inactive pills. Bleeding generally occurs only four times a year during the week when you take the last four to seven inactive pills. Formulations containing only 28 active pills — eliminating bleeding — also are available.
Additional benefits of suppressing menstruation may include:
- Relief from pain related to endometriosis or menstrual migraines
- Prevention and treatment of excessive bleeding related to uterine fibroids
- A reduction in the menstrual exacerbation of certain conditions, including seizure disorders and asthma
Combination birth control pills are an easily reversible method of contraception. Your fertility may return to normal two weeks after you stop taking combination birth control pills.
Combination birth control pills aren't appropriate for everyone, however. Your health care provider may discourage use of combination birth control pills if:
- You're breast-feeding
- You're older than age 35 and smoke
- You have a history of blood clots, stroke, breast, liver or endometrial cancer
- You have poorly controlled high blood pressure
- You have a history of or current deep vein thrombosis, pulmonary embolism or heart disease
- You have kidney, liver or adrenal gland problems
- You have migraines with aura
- You have diabetes-related complications, such as a damaged retina (retinopathy)
- You have blood-clotting problems
- You're about to be immobilized for a prolonged period due to major surgery
- You have unexplained uterine bleeding
- You're taking St. John's wort or anticonvulsants
Risks
Side effects of combination birth control pills may include:
- An increased risk of deep vein thrombosis, pulmonary embolism, heart attack, stroke and cervical cancer
- Elevated blood pressure
- Nausea
- Bloating
- Breast tenderness
- Mood changes
- Headaches
- Decreased libido
- An increase in vaginal secretions
- Breakthrough bleeding or spotting
- Changes in contact lens tolerance
Some side effects — including nausea, headaches, breast tenderness and breakthrough bleeding — may last only a few months or be less noticeable if you take the pill at the same time every day. Continuous-dosing or extended-cycle combination birth control pills are associated with a higher incidence of breakthrough or irregular bleeding.
Combination birth control pills won't protect you from sexually transmitted infections.
An estimated 8 out of 100 women who use combination birth control pills for one year will get pregnant. Although taking combination birth control pills during early pregnancy doesn't increase the risk of birth defects, it's best to stop taking birth control pills as soon as you suspect you're pregnant.
Consult your health care provider as soon as possible if you're taking combination birth control pills and have:
- Abdominal pain
- Chest pain
- New or worsening headaches
- Eye problems, such as blurred or double vision or loss of vision
- Severe leg pain or swelling
- Severe mood swings
- Depression
- Yellowish discoloration of the skin (jaundice)
- A breast lump
- A fainting attack
- A seizure
- Difficulty speaking
- A severe allergic skin rash
- Two missed periods or other signs of pregnancy
How you prepare
You'll need to request a prescription for combination birth control pills from your health care provider. Your health care provider will review your medical history and check your blood pressure. Talk to your health care provider about any medications you're taking.
It's important to discuss with your health care provider which type of combination birth control pill is right for you. Different formulations of combination birth control pills include:
- Monophasic. In this type of combination birth control pill, each active pill contains the same amount of estrogen and progestin.
- Multiphasic. In this type of combination birth control pill, the amounts of hormones in active pills vary. In a biphasic formulation, active pills contain two different combinations of estrogen and progestin. In a triphasic formulation, active pills contain three different combinations of estrogen and progestin. In some types, the progestin content steadily increases — while in others the progestin dose remains steady and the estrogen content increases.
Combination birth control pills that contain less than 50 micrograms of ethinyl estradiol, a kind of estrogen, are known as low-dose pills. Women who are sensitive to hormones may benefit from taking a lower dose pill. However, low-dose pills may result in more breakthrough bleeding than do higher dose pills.
What you can expect
To use combination birth control pills:
- Consult your health care provider about a starting date. If you use the quick-start method, you can take the first pill in the pack immediately. If you use the Sunday start, you'll take your first pill on the first Sunday following the start of your period. When using the quick start or Sunday start, use a backup method of contraception for the first week you take combination birth control pills. If you use the first-day start, you'll take your first pill on the first day of your next period. No backup method of contraception is needed.
- Pick a time to regularly take the pill. Following a routine may keep you from missing a pill.
- Follow your pill pack's instructions carefully. If you're using conventional combination birth control pills and want to have regular periods, take all of the pills in your pack and start a new pack the day after you finish your current one. If you're using conventional monophasic combination birth control pills and want to avoid monthly periods, take all of the active pills in your pack, discard the inactive pills and start taking the active pills in your next pack. Consult your health care provider about how many active pill packs you can take in a row.
- Be cautious with missed pills. If you miss an active pill, take it as soon as you remember — even if it means taking two active pills in the same day. Take the rest of the pack as usual and use a backup method of contraception for seven days. If you miss a pill, you may experience breakthrough bleeding. If you miss more than one active pill, take the last pill you missed right away. Take the rest of the pack as usual and use a backup method of contraception for seven days. If you've had unprotected sex, consult your health care provider about emergency contraception.
- Don't take breaks between packs. Always have your next pack ready before you finish your current pack.
If you take antibiotics while taking combination birth control pills, use a backup method of birth control. If you vomit within two hours after taking a combination birth control pill or have severe vomiting and diarrhea for two or more days, proceed as if you've missed a pill.
Last Updated: 2009-11-24
