Birth control pills: Learn the types and answers to common questions

For more than 60 years, a tiny pill swallowed once a day has been an effective way to help prevent pregnancy. By age 49, nearly 80 percent of women in the U.S. have used a birth control pill at some point in their lives.²

What used to be called “the pill” has come a long way. Decades of research has made hormonal birth control even more safe and effective.³

For anyone considering oral contraceptives for the first time or maybe switching from another method of birth control, the pill may be an option to consider. Talk to a health care provider and learn more about the different options below.

In this article:

What types of birth control pills are there?

Birth control pills contain synthetic forms of estrogen and progesterone, the body’s natural reproductive hormones. These lower the likelihood of becoming pregnant in different ways. Currently, there are two major categories of pills:

1. Combination pills have a type of estrogen and a progestin, a category of laboratory-made progesterone. They are the most common type of birth control pill. They work by stopping ovulation, which means the ovaries won’t release eggs for sperm to fertilize. Progestin also triggers the mucus that lines the cervix to thicken. That makes it harder for sperm to travel up reproductive pathways to reach an egg.⁴

Combination pills must be taken every day whether or not someone plans to have sex. Remember to read the product label instructions and talk to a health care provider when starting a new type of birth control.

A newer prescription oral contraceptive combines drospirenone and a different form of estrogen called estetrol.⁵

2. Progestin-only pills (also known as POPs or mini pills) contain only progestin.⁶ Doctors are more likely to prescribe the mini pill for women who may have other health issues that can be affected by taking combination birth control pills. These might include diabetes, heart disease, high blood pressure, migraines with auras or a history of blood clots.⁷

Traditional progestin-only pills come in 28-day packs without hormone-free inactive pills, so they must be taken continuously.⁸ Even taking the hormone daily, a person may get their period in the fourth week or have irregular bleeding or spotting throughout the month.⁹

Because the mini pill has less effect on ovulation, it is especially important to take it every day and at the same time each day.¹⁰ A missed dose happens when a person forgets to take the mini pill within three hours of their normal time.¹¹

Another form of progestin, the drospirenone-only pill, may also be an option, especially for women who experience irregular bleeding with the mini pill.¹². It comes in a 28-day pack with four inactive pills.¹³ It does a better job of suppressing ovulation than a traditional mini pill.¹⁴ While a person should still take the pill at the same time each day, it has a wider window for missed doses than a traditional mini pill.^15, 16

An over-the-counter (OTC) oral contraceptive known as Opill was recently approved by the Food and Drug Administration (FDA) and is now available to buy.¹⁷ Its active hormone is norgestrel, a type of progestin. Like the mini pill, it will thicken cervical mucus but not suppress every ovulation in women, and it must be taken at the same time every day.¹⁸

What are some birth control pill side effects?

Birth control pills are generally safe and effective, but a few common side effects are:¹⁹

• Breast tenderness
• Headache
• Mood changes²⁰
• Nausea 
• Spotting or bleeding between periods 

Most side effects are mild and may subside after a person has been taking the pill for a while.^{21, 22}

Less commonly, some people may develop high blood pressure. The pills, particularly those with estrogen, have also been linked to blood clots, heart attacks and strokes.²³ However, birth control regimens have changed over time with improved safety.²⁴ For people older than 35 who smoke, or if a person has a history of blood clots or breast cancer, a health care provider may advise them not to take combination birth control pills.^{25, 26}

In any case, it’s important to talk with a health care provider or gynecologist regularly if someone is taking these pills or plans to take them and be sure to share any side effects or irregular bleeding.

Do birth control pills make a person gain weight?

Oral contraceptives have not been shown to cause significant weight gain or loss.²⁷ Some people may gain a little weight, but in general, we also gain weight as we get older.²⁸

How effective are birth control pills?

The good news: If used perfectly without missing a dose, oral contraceptives are more than 99 percent effective. That means less than 1 in 100 women who take the pill become pregnant each year.²⁹ Be sure to read the product label for directions and safety information.

Of course, no one is perfect. A person may miss a dose, misplace their pill pack or forget to refill a prescription. Effectiveness drops to 93 percent with what researchers call “typical use” when products aren’t used as directed.³⁰

A few medications can also interfere with birth control pills. The most common are seizure medications, like topiramate. The antibiotic rifampin,³¹ the antifungal griseofulvin³² and the herb St. John’s wort³³ are other things that may make birth control pills less effective.³⁴ Make sure to tell a health care provider about any current medications or supplements.

On the topic of effectiveness, remember that oral contraceptives don’t guard against sexually transmitted infections (STIs).³⁵

How soon do birth control pills work?

Oral contraceptives need some time to become effective — typically from 2 to 7 days, depending on the type of pill and where in the menstrual cycle a person is when they start them.³⁶ So for the week after starting either the combined or mini pill, consider using a barrier birth control method, such as a condom or a contraceptive sponge.³⁷

How long can it take someone to get pregnant after they stop using birth control pills?

When a person stops using birth control, it’s possible to get pregnant right away, even if they haven’t had their period yet.³⁸ Someone can go off birth control at any point in their cycle, and their body will begin to return to the way it was before using birth control. They may have irregular periods for a few months or experience spotting or bleeding between periods.³⁹ They may find it helpful to track their cycle after stopping birth control.

What if someone misses a dose of their birth control pill?

Getting back on track depends on which oral contraceptive a person takes and whether they’re off schedule by a few hours or a few days. Read the package instructions or speak to a health care provider if this happens.

This content is for informational purposes only and is not medical advice. Consult your health care provider before taking any vitamins or supplements and prior to beginning or changing any health care practices.