Emergency contraception is often confused with abortion pills – here’s how Plan B and other generic versions work to prevent pregnancy

Since the overturning of Roe v. Wade in June 2022 and the end of constitutional protection for abortion, emergency contraception has become more difficult to obtain and – more than ever – shrouded in misinformation.

Attempting to control inventory, Amazon, Rite Aid and Walmart have imposed purchase limits on the emergency contraception known as Plan B since the Supreme Court’s ruling. Panicked buyers have been trying to stock up on the drug in case it becomes unavailable.

Several legislators and proposed bills have conflated emergency contraception with abortion and are trying to limit access to it. The recent court ruling blocking access to mifepristone – which has been approved by the FDA since 2000 – is an ominous sign to many that emergency contraception could be the next target.

Regardless of one’s stance on abortion, it is important to understand why emergency contraception should be a basic component of women’s reproductive health care and family planning services. As a researcher of women’s sexual and reproductive health and decision-making, I have extensively researched access to emergency contraception.

What is emergency contraception?

Emergency contraception is the only way to prevent pregnancy after sex has already occurred. It can be used when no contraception was used or it was used incorrectly, such as with missed birth control pills or broken condoms. Emergency contraception is also used to prevent pregnancy after sexual assault or rape.

Emergency contraception can take the form of pills – sometimes called the morning-after pill – or an intrauterine device, or IUD that delays ovulation.

There are two types of emergency contraception pills. The most widely known is levonorgestrel, which is sold in the U.S. under the brand name Plan B, along with numerous generic versions.

Levonorgestrel was first approved for over-the-counter sale to women 18 and older in 2006, and in 2013 age restrictions were removed.

The second type of emergency contraception pill is ulipristal acetate, which is sold under the brand name ella. Both Plan B and ella work by delaying ovulation. In addition, ella also thins the uterus lining so that even if an egg were fertilized, it is harder for it to implant in the uterus to start a pregnancy.

Both types of pills are effective at preventing pregnancy. Plan B is most effective if taken within three days of sex, with some declining effectiveness on days four and five. Ella is effective if taken within five days of sex and, unlike Plan B, is equally effective all five days.

The most effective types of emergency contraception are IUDs that are inserted by a health care provider. Copper IUDs – also referred to as nonhormonal IUDs – are sold under the brand name Paragard. They release into the uterus copper ions that are toxic to both eggs and sperm. This allows them to be used as emergency contraception if inserted within five days after sex, and as ongoing contraception for up to 10 years.

Levonorgestrel IUDs – referred to as hormonal IUDs – are sold under the brand names Mirena, Liletta, Kyleena and Skyla. The levonorgestrel released into the uterus makes the mucus around the cervix thicker so that a sperm cannot penetrate to fertilize the egg, and it is as effective as the copper IUD when inserted as emergency contraception for up to five days after sex. Both Paragard and Mirena IUDs have been approved by the FDA for use as contraception, but they are not yet approved specifically for use as emergency contraception.

How is emergency contraception different from the abortion pill?

For many years, the way that emergency contraception works has been misunderstood. There has been confusion about whether emergency contraception is an abortifacient – that is, a medication that triggers an abortion. The key difference is that the abortion pill works only when a woman is pregnant, and emergency contraception works only when she is not.

The so-called abortion pill is used for a medication abortion and actually consists of two separate pills that do different things.

The first of these pills is mifepristone, which functions to block production of the pregnancy hormone progesterone so that the uterus lining thins and the embryo detaches from it. This is the pill that is receiving national attention because of clashing court rulings over access, a battle that is headed to the Supreme Court.

The second pill, misoprostol, stimulates contractions in the uterus to eject the embryo and gestational sac. Emergency contraception prevents a pregnancy before it occurs, whereas the abortion pill ends a pregnancy once it’s begun.

How do abortion restrictions jeopardize emergency contraception?

With the increase in abortion restrictions, access to a full range of contraceptive options – including emergency contraception – is more critical than ever.

There are already numerous barriers to obtaining emergency contraception in a timely manner. The most effective types of emergency contraception, ulipristal acetate and both hormonal and nonhormonal IUDs, must be obtained from a health care provider. This means a woman needs an appointment – usually available only on a weekday during business hours – as well as transportation and the means to pay for the appointment, either through health insurance or self-pay. She may need to take time off of work to attend the appointment, or she may need to obtain child care.

For many women in poor, rural or geographically isolated neighborhoods, these barriers are difficult to surmount. This is particularly true given the short window of time in which emergency contraception is effective.

Levonorgestrel emergency contraception pills are available over the counter and should be easily accessible, but individuals trying to purchase them run into numerous obstacles. These include low stocks in pharmacies – especially independent pharmacies – and point-of-sale restrictions, such as requirements that purchasers be a certain age, show identification or have parental consent. People also encounter high rates of misinformation about when to take levonorgestrel for maximum effectiveness and about sales restrictions. Finally, they encounter pharmacy staff who object to selling it because they misunderstand how it works.

The surge in demand for emergency contraception since the reversal of Roe v. Wade and the purchase limits put on it by retailers have exacerbated these access challenges.

What are the benefits of emergency contraception?

Access to emergency contraception promotes women’s health in several ways. Nearly half of pregnancies in the U.S. are unintended, and emergency contraception can prevent about 95% of unwanted or mistimed pregnancies when used within five days of sex. It can also be used as a backup option when another form of contraception fails. And it can be given to survivors of sexual assault. Emergency contraception also reduces the need for abortions.

Overall, access to a full range of contraceptive options – including emergency contraception – gives women greater control over their reproductive choices. The ability to control the number and spacing of their pregnancies improves the health, social and economic outcomes of both women and their families.