A woman choosing a birth control pill

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Birth Control

Birth control pills 101

Everything you need to know about oral contraceptives

by Kate Wahl, Science writer for Clue. Reviewed by Sarah Toler, DNP, Science Writer for Clue
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Top things to know:

  • Combination pills today have less estrogen than the original estrogen-progestin pills

  • What kind of contraception you choose to use depends on how you value different benefits, side effects, and other factors

  • Generic birth control is considered bioequivalent and pharmaceutically equivalent to branded products

Oral contraceptives are used by more than 100 million people globally and combination oral contraceptive pills (COCs) containing estrogen and progestin are one of the 50 most commonly prescribed medications in the US (1,2). Birth control pills are the most common form of reversible contraception in the United States (3). 

There are three types of pill:

  • the cyclic COC that causes monthly period-type bleeding

  • the extended use COC pill, which can be taken for longer periods of time with less period-type bleeding,

  • the progestin-only pill (POP), which is estrogen-free (2).

The cyclic COC pill we’ve come to know and love (or hate) was approved as a method of birth control in 1960 and POPs came along about 10 years later (2). The extended use COC became available in 2003 (84 active pills in a row, then 7 placebo pills), with a continuous pill (no placebo pills) arriving on the scene in 2007 (4).

Let's go over what has changed since the invention of the pill, what could be coming in the future, and how to choose a pill (or other type of contraception) that’s right for you.

Birth control pills past and present

Since their invention, birth control pills have evolved into many different formats:

  • Lower levels of hormones: The original COC contained more estrogen and progestin than the versions we have today (2,5). Because the amount of estrogen in the pill was associated with increased risk of stroke, heart attack, and other negative outcomes, pills today contain about 20% to 50% of the original amount estrogen (learn more about the side effects of hormonal contraception) (6). The types of estrogen and progestin in oral contraceptives have also changed and, by definition, POPs don’t contain any estrogen at all. 

  • More phases: The first COC was monophasic: every active pill had the same amount of estrogen and progestin (2). In the 1980s, pharmaceutical companies introduced biphasic (two different hormone doses in a treatment cycle) and triphasic (you guessed it, three different hormone doses per cycle) pills, and the first four-phase pill became available in the US in 2010 (2,7). Currently, it looks like there aren’t big differences between the monophasic pill and different multi-phase pills, although there isn’t enough research to know for sure (8–10).

  • Extended use: COCs were initially designed to mimic the 28-day menstrual cycle, with 21 active pills containing hormones followed by 7 inactive pills to cause withdrawal bleeding. Now, some options use different combinations of active and inactive pills including 84 active pills with 7 inactive pills or no placebo pills at all, like POPs (4). Research shows that compared to cyclic pills, extended and continuous use COCs have about the same number of bleeding days but are associated with improvements in bleeding-related symptoms like headaches, tiredness, bloating, and cramping (11).

What is the future of birth control pills?

Every type of birth control pill requires that the active pills are taken daily. This isn’t always what people are looking for—one study showed that 30% of pill users have stopped using oral contraceptives because they were dissatisfied (12). 

Researchers are trying to come up with new kinds of birth control pills (a pill that is only taken at the time of sex and the elusive male birth control pill, for example (13,14), but the process is slow because of the high cost and potential risks of developing innovative products (15). 

Which pill is right for me?

There are several reasons why someone might want to use birth control pills rather than other methods. For instance, they might prefer to take their medication orally rather than through a patch or injection. Or, the up-front cost of the pill may be the most affordable for them. 

If you don’t have time to wait for the male birth control pill and the words monophasic, biphasic, triphasic, quadriphasic, and extended use make your head spin, you’re not alone. A lot of factors go into choosing a method of contraception! 

There isn’t a lot of research yet that compares types of birth control pills, but here is a short list of some features that make each of the  three main oral contraceptives unique to consider when making your decision:

  • Cyclic COC: Compared to other types of pills, cyclic COCs result in bleeding that mimics a period, with good control of bleeding cycle regularity (aka less spotting) (16).

  • POP: Unlike COCs, POPs can be used by people who can’t use estrogen, including those who are breastfeeding (beginning 6 weeks postpartum), people who smoke and are over the age of 35, people with obesity, and people who want to avoid estrogen-related symptoms (16). 

  • Extended Use COC: As we’ve already learned, extended use pills may result in fewer days of “flow” than cyclic COCs as well as fewer related symptoms like headaches, tiredness, bloating, and cramping (11).

In addition to preventing pregnancy, birth control pills and hormonal contraceptives in general may have other benefits. These include bleeding regularity, treatment of heavy bleeding, treatment of painful periods, elimination of bleeding, treatment of PMS, decreased risk of certain cancers, treatment of acne or male-pattern hair growth, improved bone mineral density, and treatment of pelvic pain due to endometriosis (17). 

Speak with your healthcare provider about which factors are important to you, when considering a birth control method, and they can help you decide. 

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Brand or generic? 

Back in the early days of the pill, the Planned Parenthood Federation of America did not use generic oral contraceptives, likely out of concern about how these compared to the branded versions (19). This rule is long gone, but we still hear about people who experience new symptoms when they switch to generic (20). 

On the other hand, using generics can be cost-saving and, to be approved for use in the US, companies need to show that their generic medication is bioequivalent (similar absorption by the body) and pharmaceutically equivalent (same strength and dose of active ingredients) to the branded product (21). 

So what does this mean for you? Here’s what the American College of Obstetricians and Gynecologists (ACOG) has to say, “The U.S. Food and Drug Administration considers generic and brand name oral contraceptive products clinically equivalent and interchangeable. [ACOG] supports patient or clinician requests for branded OCs or continuation of the same generic or branded oral contraceptives if the request is based on clinical experience or concerns regarding packaging or compliance, or if the branded product is considered a better choice for that individual patient.” (20) Translation: You should be able to use birth control that is safe for you and meets your needs.

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