Combination Pills

What are Combination Pills?

Combination pills, also called “combo pills,” contain a combination of the hormones estrogen and progestin that prevent pregnancy by preventing ovulation, thickening the cervical mucus, or changing the endometrial lining of the uterus.

There are two methods for taking combination pills. The most common method is the conventional method, in which pills are taken in monthly packs. Most monthly packs include 21 or 28 days’ worth of pills.

·      In a 28-day pack, there are 21 “active” pills, all of which contain estrogen and progestin, and the last seven pills are “inactive” or placebo pills that contain no hormones.

·      A 21-day pack contains 21 pills that are all active pills, and no pills are taken for the last seven days.1 Bleeding typically occurs once per month, during the days in which no active pills are taken.2

Another method is called the continuous or extended method, which is designed to reduce the number of menstrual periods per year.1 Most continuous-pill packs have 84 active pills in a row (about three months’ worth of pills), followed by seven inactive pills. Bleeding occurs during the seven days the inactive pills are taken, resulting in only four periods per year. There are also pill formulations that contain 28 active pills each month and eliminate menstrual bleeding altogether.2

There can be many variations of pill packs for the conventional or continuous method. Each contains different amounts of hormones that protect against pregnancy everyday, whether the hormonal or inactive pills are taken. With monophasic formulations, each active pill contains the same amount of estrogen and progestin; with biphasic and triphasic formulations, the amount of hormones in each pill varies as the pack goes on.2 Every female is different and will find that some methods and variations will work better than others.

How Combination Pills Work

Combination pills contain the hormones progestin and estrogen that prevent pregnancy by thickening cervical mucus so that sperm cannot pass through the cervix to the uterus or fallopian tubes to fertilize an egg. These hormones also suppress ovulation (the release of an egg from the ovaries) and change the lining of the uterus to further prevent fertilization and implantation of an egg.1

How Combo Pills Should Be Taken

A woman can begin to take the pill at any time. If a pill pack is started within five days after the start of the menstrual period, it is called a “first day start.” A “Sunday start” involves taking the first pill of a pack the Sunday following a menstrual period. A “quick start” is when the first pill is taken immediately, regardless of the current phase of the menstrual cycle.2 For a first-day starter, the pill will begin working right away, although it would be a good idea to use a backup contraceptive (such as a male condom) for at least a week after starting the pill. If the pack is started at any other time during the menstrual cycle, as with a Sunday or quick-start pack, a woman may not be fully protected for about a week. A backup method should be used for the first seven days after starting the pill to avoid pregnancy.1

The pill can be taken right after an abortion or miscarriage. It is best to wait at least three weeks after giving birth to start taking the combo pill. A woman should wait six weeks if she is breastfeeding because the estrogen in the pill can inhibit milk production and be harmful to a developing infant.1

Because the hormones in the pill can cause unfortunate side effects such as weight gain, nausea, or moodiness, it is generally recommended that women take the lowest dose of hormones possible. This way, the pill will protect against pregnancy with little to no side effects.2 A doctor will be able to determine the correct amount of hormones for a specific woman.

What to do if You Miss a Pill

It is strongly recommended that a backup birth control method (such as a condom) be used for at least seven days following a missed pill to prevent pregnancy. This may be more important for some types of pills than others, depending on the amount of hormones in the pill. If you have unprotected sex at any time during the seven days following a missed pill, consider using emergency contraception.1 Most pill packs will come with specific instructions for what to do if you miss a pill, but in general, you can follow the instructions below.

Instructions For Conventional Method Users

·      If you miss any number of active pills during week one of the cycle, take one active pill as soon as you remember and continue the rest of the pack as usual—this means that you may have to take two pills in one day.

·      If you miss one or two active pills during week two or three of the cycle, take one active pill as soon as you remember and continue the pack as usual until the end of the third week. Start a new pack at the end of week three instead of taking a hormone-free week. You may experience bleeding, but continue to take the active pills.

·      If you miss three or more pills during week two or three of your cycle, take one active pill as soon as you remember and continue to take the rest of the pack as usual. At the end of week three, discard any placebo pills and start a new pack immediately. It is especially important to use a backup birth control method if you miss any pills during this time. 

·      If you miss any inactive pills during week four, throw the missed pills away. There is actually no need to take these pills anyway, as they are just reminders. But remember to start a new pack of pills no more than seven days after your last active pill.3

Instructions for Continuous/Extended Method Users

·      If you miss any pills on day one through 21, follow the instructions for the conventional method above.

·      You can miss up to seven active pills in a row after day 21, but you should never go more than seven days without taking any hormones, as this will greatly increase the risk of pregnancy.

·      If you miss more than seven active pills after day 21, take one active pill as soon as you remember and continue the pack as usual, and remember to use a backup method of birth control.3

Combination Pill vs. Progestin-Only Pill

You should not take the combination pill if you

·      Are older than 35 and smoke cigarettes

·      Get frequent migraine headaches

·      Have blood clotting disorders or are being treated for blood clots

·      Have had a heart attack, stroke, angina, or other serious heart problem

·      Have lupus

·      Have liver disease or liver cancer

·      Have diabetes

·      Have uncontrollable high blood pressure

·      Are or will be on bed rest for a prolonged period of time1

All of these risk factors may be caused or worsened by the estrogen in combination pills. You should also not take the combo pill if you are breastfeeding because the estrogen in the pills can interfere with milk production. If any of these health restrictions apply to you, you may want to consider other types of contraception, or even progestin-only birth control pills.2 Progestin only pills do not contain estrogen, and therefore do not have such severe side affects associated with taking them. However, progestin-only pills are much more time sensitive and do not carry some of the advantages that combination pills do. It is best to talk with your doctor or clinician about which pill best accommodates your needs.

Effectiveness of Combination Pills

“Perfect use” means that the pill is taken everyday, exactly as directed, with no mistakes or missed pills—thus, the perfect-use failure rate is quite low. “Typical use” is slightly more realistic of how users will take the pill, which accounts for periodic mistakes or missed pills. The combination pill has a failure rate of 1% when women are “perfect” users. This means that one oral contraceptive user out of 100 will become pregnant within one year if the pill is used as instructed. The failure rate among “typical” users is 9%, meaning that nine oral contraceptive users out of 100 will become pregnant within one year under typical conditions.

The effectiveness of the combination pill is dependent upon multiple factors. The largest factor is the regularity with which the pill is taken. In addition, the pill may be less effective for women who are overweight or who are experiencing vomiting and diarrhea. Certain medications, such as antibiotics, HIV medications, and anti-seizure medications can also reduce the effectiveness of the pill. Using the pill in conjunction with a barrier contraceptive, such as the female condom or male condom, can further reduce the chances of fertilization.1

Birth control pills do NOT protect against the transmission of sexually transmitted infections (STIs). To reduce the risk of contracting and spreading STIs, always use a condom and get tested.


·      Combination pills can significantly reduce menstrual cramps and premenstrual syndrome (PMS) symptoms, such as headaches, menstrual migraines, irritability and depression.

·      The estrogen in the pills regulates periods and can make them lighter and/or shorter.

·      Many women experience reduced acne and an increase in breast size.

·      The pill can protect against many health problems, including pelvic inflammatory disease, bone thinning, ectopic pregnancy, endometrial and ovarian cancers, infection of the fallopian tubes, ovaries, and uterus, iron-deficiency anemia, cysts in the breasts or ovaries, uterine fibroids, and breast tumors (both benign and cancerous)1

·      Should you decide that you want to become pregnant, you can stop taking the pill at any time. The pill is immediately reversible, which means that you could become pregnant right away; for most women, however, fertility returns to normal after about two weeks of pill discontinuation.

·      When using continuous or extended cycle pills, there are fewer periods per year.

·      Continuous cycle pills can also provide relief from the pain of endometriosis.2

·      You can skip the placebo pills and continue to take active pills for up to three (sometimes four) months if you wish to have fewer periods. This is especially convenient for people who travel frequently. Discuss this with your doctor before trying it.

·      Oral contraceptives allow for sexual spontaneity.


·      The pill does not protect against STIs.

·      The combination pill is somewhat time sensitive: it must be taken every day for maximum protection against pregnancy.

·      The pills have many normal side effects, such as bleeding or spotting between periods (This is even more common with continuous cycle pills), breast tenderness, nausea, vomiting, mood changes and/or depression, Weight gain and increase in breast size, and headaches (These will usually clear up within two to three months).

·      The hormones in the pill may lower sexual desire.

·      It can take anywhere between one to six months for periods to be regulated after stopping the pill, though it is possible to become pregnant immediately after stopping.1

·      There is a slight possibility of developing blood clots. The possibility of this happening is very rare and is most likely to occur in cases wherein someone is immobilized or confined to a bed.

·      Some pills have a higher risk for blood clots and associated health problems than others, so it is a good idea to talk to a doctor about your pill regime and its associated risk of heart and health problems.1

·      Certain prescription medications or antibiotics can decrease the effectiveness of the pill. You should speak to your doctor to see if you are taking any prescriptions or supplements that could interfere with the pill. If the medication you are taking is one that decreases the effectiveness of the pill, you should abstain from intercourse or use a backup method of birth control, such as a condom, until you are no longer on that medication.

·      The pill typically requires a prescription from a doctor or a visit to a clinic.

Abnormal Symptoms

It is important to see a doctor if any one of the normal symptoms above is persistent or worsens in any way.

Serious side effects are rare but can happen. They may include any of the following:

·      Heart attack or stroke

·      Blood clots in the legs, lungs, heart, or brain

·      High blood pressure

·      Liver tumors

·      Gallstones

·      Jaundice


If you experience any of the following symptoms, report them to your doctor immediately:

·      New lumps in the breasts

·      A sudden, severe headache that worsens or happens more often than usual

·      Achy soreness in the leg

·      Aura

·      Chest or abdominal pain

·      A sudden missed period after a serious of regular periods

·      Difficulty breathing

·      Yellowing of the skin or eyes

·      Depression

·      Blurred Vision

·      Fainting

·      Severe skin rash

·      Seizure

The pill has been said to increase the risk of breast cancer in some women. However, most recent medical literature suggests that the pill has little to no effect on the increased risk of developing breast cancer. In fact, the pill may help to prevent breast cancer along with endometrial and ovarian cancer.1


For more information about the various types of birth control, click here!



1. "Birth Control Pills." Planned Parenthood, n.d. Web. 17 Apr. 2014. <

2. "Combination Birth Control Pills." Mayo Clinic, n.d. Web. 18 Apr. 2014. <

3. "The Pill." McKinley Health Center, University of Illinois, n.d. Web. 18 Apr. 2014. <>.


Last Updated 18 April 2014.