Your Guide to Birth Control Pills (Oral Contraceptives)

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on May 12, 2025.

How effective is the birth control pill?

The birth control pill is a popular and highly effective method of birth control. The pill has a less than a 1% failure rate - meaning less than 1 out of 100 women unintentionally become pregnant - when the pill is used correctly. For women who miss taking their pills, the failure rate goes up to roughly 8%, or 8 out of 100 women become pregnant unintentionally.

Missing your pill, taking it with other medications, or being sick (like with diarrhea or vomiting) may also decrease how well your pill works.

Roughly 85% of women who do not use birth control and are trying to get pregnant will conceive within one year. If you do not want to become pregnant, but you may have trouble remembering to take a pill each day, you might consider a longer-acting form of birth control, such as these examples: the shot, patch, implant, vaginal ring or IUD. 

What are birth control pills used for?

A birth control pill (sometimes called an oral contraceptive) is a pill that you take by mouth to prevent pregnancy. Birth control pills work by stopping the ovaries from releasing eggs and thickens the cervical mucus, which keeps sperm from fertilizing the egg.

In general, the birth control pills come in 3 forms: combination pills contain two hormones, progestin and estrogen, “mini-pills” that contain only progestin and continuous or extended-use pills. Generally, combination birth control pills are slightly more effective than progestin-only birth control pills.

Combination pills are available in 21-day packs (with 21 active tablets) or 28-day packs (with 21 active tablets and 7 inactive ("reminder") tablets). Extended-cycle pills such as Seasonique contain 84 active tablets and 7 inactive tablets (91 pills total). The inactive pills are included to help you remember when to start a new pack of pills.

The menstrual cycle occurs during the time period when the inactive pills are taken. If the inactive pills are missed, there is no chance this would result in a pregnancy. However, it is important to start the new pack and active pills on the correct day.

Opill: An Over-the-Counter (OTC) Birth Control Pill

Opill over-the-counter (OTC) birth control pill became available in March 2024 to help prevent pregnancy. Most birth control pills require a prescription, but a new OTC birth control pill called Opill (norgestrel 0.075 mg) is now available in pharmacies, retailers and online. Check with your pharmacy for availability.

Opill is a progestin-only pill (POP), often referred to as a “mini-pill”. It does not contain estrogen, another hormone also found in combination birth control pills.

Opill is taken once daily, at the same time each day. It works by thickening the cervical mucus to help prevent sperm from fertilizing the egg, thins the uterine lining and may prevent the ovaries from releasing eggs (ovulation) in some cycles. 

The most common side effects of Opill include irregular bleeding, headaches, dizziness, nausea, increased appetite, abdominal (stomach) pain, cramps or bloating. 

Opill should not be used by those who have or have ever had breast cancer. If you have had any other form of cancer should ask a doctor before use. Opill also should not be used together with other hormonal birth control products (such as another oral birth control pill, a vaginal ring, a contraceptive patch, a contraceptive implant, a contraceptive injection or an IUD/intra-uterine device).

How do I take Opill?

• Take 1 tablet by mouth at the same time every day (and no later than 3 hours from the time you took your tablet the day before). Take your pill at the same time of day, every day.
• Never skip your daily tablet, even if you do not have sex very often or have a menstrual (period) change. Use a condom (or another barrier method) every time you have sex during the first 2 days (48 hours) after starting Opill because it takes 2 days to start working.
• Each pack of Opill contains 28 pills. You can start your pack on any day. Do not take a break between packs. When you finish one pack (all 28 tablets), you should start the next pack the following day.

Learn more: What is Opill, how can I get it and how much does it cost?

Are birth control pills free?

Birth control pills are typically free for women under the Affordable Care Act (ACA) and if you have insurance. Most insurance plans must cover the cost of any birth control method, including the pill. Your insurance may only cover certain brands or generic versions, so check with them for options or ask your pharmacist for help.

Birth control pills are usually affordable, depending upon health insurance coverage and generic availability. In general, you should be able to get birth control pills from $10 to $50 per month if you pay cash, although there are other more expensive options.

Many birth control pills are available generically and have a lower price. Again, if you have prescription drug insurance, your birth control (all types) should be free under the Affordable Care Act. If you have trouble affording your birth control, talk to your health care provider or pharmacist who may be able to suggest more affordable options.

What are the advantages to the birth control pill?

If the birth control pill is taken correctly, it has a high level of effectiveness to prevent pregnancy in a relatively convenient manner. But other advantages to taking the pill for many women include:

• Lighter, less frequent or no periods may be possible depending upon the type of pill taken and dosing schedule. The birth control pill can lessen heavy bleeding, pain and severity of endometriosis and fibroid tumors.
• Reduce pain and cramping during menstruation
• Acne or premenstrual dysphoric disorder (PMDD) may improve with some birth control pills. 
• Prevent ovulation and pregnancy in women with primary ovarian insufficiency (POI).
• The use of the birth control pill can lower the risk of pelvic inflammatory disease, uterine cancer and ovarian cancer.
• The progestin-only forms may be used by women who are breast-feeding or cannot use estrogen for medical reasons.
• Reduce the symptoms of endometriosis, polycystic ovary syndrome (PCOS), premenstrual syndrome or premenstrual dysphoric disorder (PMDD).

What is the best birth control pill?

The best birth control for someone else may not always be the best option for you, so it's difficult to answer this question. Safety, cost, availability and your lifestyle are factors that have to be considered. You should always make this decision with the advice of your healthcare provider.

Commonly used combination birth control pills include:

• Apri
• Lo Loestrin Fe
• Sprintec
• Yaz
• Junel Fe 1/20
• Levora
• Sprintec
• Tri-Sprintec
• Microgestin Fe
• Yasmin
• Aviane
• Xulane

Consult with your healthcare provider to discuss birth control options in more detail.

A monthly period still occurs with the traditional, combination birth control pills. Women may also choose the extended or continuous dosing birth control pill, in which a period only occurs 4 times a year (like with Seasonique) or is completely eliminated (like with Amethyst) - although spotting may still occur.

It is also possible to completely eliminate periods by taking only the active pills continuously (every day) from a combination birth control pill package, and skipping the inactive pills. Ask your healthcare provider if this would be a good option for you. You may also run into problems with insurance coverage, so check with your plan.

What is the mini-pill or progestin-only birth control pill?

The progestin-only or “mini-pill” contains only norethindrone or drospirenone (which are progestins) and each pill is active (there are no placebo or inactive pills in the pack). When you finish one pack of progestin-only pills, you start another pack the very next day.

With progestin-only pills you will either get your period in the fourth week, get no periods, or have spotting during the month. Your periods may be heavier or lighter. 

Examples of progestin-only pills include:

• Camila
• Errin
• Heather
• Incassia
• Lyza
• Slynd

See other progestin-only birth control options

Most progestin-only pills (mini-pills) MUST be taken at the same time each day (no more than 3 hours late), except for Slynd. If you miss a pill, you will increase your chances of releasing an egg that could be fertilized, leading to pregnancy.

Slynd (drospirenone, 4 mg) is a progestin-only oral contraceptive pill with a dosing regimen that contains 24 active and 4 inactive tablets and also allows a 24-hour missed pill window.

What if I miss my birth control pill?

• With so many different types of birth control pills on the market today, it's best to look up the specific instructions for a missed pill in the package insert for your exact pill name.
• You can search for your pill here, or call your doctor, nurse or pharmacist right away for specific instructions.

In general, if you forget to take an active combined oral contraceptive pill (with both estrogen and progestin), you should take it as soon as possible and take the next one at the usual time it is due. This means you might take 2 pills in the same day. If you miss more than two pills, use a backup method of birth control (eg, condoms) for seven days.

For most progestin-only ("mini") birth control pills (except Slynd), a backup method of birth control should be used for 48 hours (2 days in a row) if a dose is missed or taken 3 hours late. Continue to take your mini-pills daily on your regular schedule at the same time, even if you have to take 2 pills at the same time.

View instructions here for "What happens if I miss a dose" for the Slynd progestin-only pill.

Learn More: Missed your birth control pill? Here's what to do

If you cannot find out what to do about your missed pill or pills, use a back-up method of birth control, such as a condom or diaphragm with a spermicide, until you speak with your healthcare provider.

If you miss three combination pills in a row, call your healthcare provider. You may need to stop using your current birth control pack and start a new pack while using a back up method of birth control (like a condom). In some cases you may need to use an emergency contraceptive such as Plan B One Step.

Related: Emergency Contraception: What You Need to Know

If you miss a period, call your doctor because you might be pregnant and you'll need to take a pregnancy test.

Is the birth control pill safe?

Women should talk to their healthcare professional about their individual risk profile before deciding which type of birth control method to use. 

Birth control pills should not be used by women who have a history of:

• increased risk of blood clotting, stroke risk
• uncontrolled high blood pressure or heart disease
• breast cancer
• endometrial cancer
• undiagnosed vaginal bleeding
• chest pain
• severe headaches
• uncontrolled diabetes
• liver tumors or liver disease
• or if currently pregnant

Smoking increases the risk of serious heart side effects when using a combined estrogen and progestin birth control, including the ring or the patch. Combination estrogen and progestin birth control should NOT be used in women over 35 years of age who smoke due to an increased risk of rare but serious side effects, such as heart attack, blood clots, and stroke.

You should not use birth control if you have diabetes mellitus and are over age 35, diabetes mellitus with hypertension or with vascular disease or other end-organ damage, or diabetes mellitus of > 20 years duration.

Heart risks linked with the pill increase with:

• age
• weight
• family history of heart disease
• number of cigarettes smoked per day.

Let your physician know if you have migraine headaches when discussing birth control options.

The birth control pill does not protect against any form of sexually transmitted disease (STD), including HIV / AIDS. A male latex or female condom should be used in combination with any other form of birth control if protection against STDs is needed.

There may be certain medications that interact with your birth control pill and may change the effectiveness of either medicine. Let your healthcare providers know about all of the medicines you take, including prescription, over-the-counter (OTC), vitamins, and herbal and dietary supplement medicines. Be sure not to stop taking any medicines without your doctor's approval first.

Can I take the pill If I'm breastfeeding?

Breastfeeding mothers should avoid the estrogen in combined hormonal birth control for at least 4 weeks after delivery as it may reduce milk supply and can increase the risk of a blood clot. After 4 weeks, low-dose estrogen, combined oral contraceptives may be a reasonable option, but check with your doctor based on any health conditions you have.

Birth control options for breastfeeding women include:

• IUDs
• progestin only pills (“mini-pills”)
• the implant
• the birth control shot
• condoms

Common side effects with birth control pills

• Spotting between periods
• Possible weight gain
• Breast swelling or tenderness
• Nausea or upset stomach
• Mood changes

Serious side effects with birth control pills

• Blurred vision
• Severe stomach pain
• Severe headache
• Swelling or pain in the legs
• Chest pain, heart attack, blood clots, stroke

Other warnings and side effects exist for birth control pills. It is important to review the specific consumer information for your specific birth control and discuss any questions or concerns with your healthcare provider.

Generic options of birth control pills may be available; check with your pharmacist for cost-savings, if needed.

Tell your healthcare provider about all other medications you take, including prescription, over-the-counter, vitamin and herbal supplements. Certain medications may make your birth control less effective. Be sure you have complete drug interaction review each time you start a new medication.

Table 1: Common Birth Control Pills

This may not be a complete list. For other options, generic and proprietary names, also see: Oral Contraceptives

This is not all the information you need to know about birth control (contraceptives) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

See also

• Birth Control Pills - When Should I Expect My Period?
• Birth Control Pills: Benefits, Risks & Side Effects
• Birth Control Pills: Why do I get breakthrough bleeding?
• Emergency Contraception: What You Need to Know
• Emergency Contraceptives: Morning After Pills & OTC Options
• Grapefruit and Birth Control Pills: Your Questions Answered
• Missed your birth control pill? Here's what to do
• Non-hormonal Methods of Birth Control
• What are the options for permanent birth control?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer