emergency contraception basics

Emergency contraception (EC) is sometimes called the morning-after pill or Plan B. It is contraception used as soon as possible up to 5 days after unprotected sex if contraception isn’t used, contraception fails, or when sex is coerced or forced.


There are two kinds of EC pills:

  • Progestin-only EC (Plan B One-Step and generics like AfterPill) is available over-the-counter (OTC).
  • Ulipristal acetate EC (sold as ella) is available with prescription only.

A copper IUD inserted within 5 days after unprotected sex can also be used as EC, and it has the added benefit of providing long-term pregnancy prevention. New research shows that a hormonal IUD (like Mirena) may also be an effective option for EC.


EC is NOT the same as the abortion pill; EC prevents pregnancy before it happens.


How does EC work?

  • EC pills prevent or delay ovulation (release of an egg from the ovary). If there’s no egg, there’s nothing for sperm to fertilize and pregnancy can’t occur.
  • If someone is already pregnant, taking EC will not harm or end the pregnancy. EC is not the same as the abortion pill.

Is EC safe?

  • EC is extremely safe. The FDA has approved EC for unrestricted over-the-counter access – and in fact, EC is safer than many OTC drugs, such as Tylenol.
  • Side effects (such as nausea, headache, and changes to the next period) are generally mild and go away on their own. Many people don’t experience any side effects at all.
  • EC won’t harm a pregnancy if someone takes it while pregnant or gets pregnant after taking it.
  • Taking EC – even multiple times within the same month or year – does not affect one’s ability to get pregnant in the future.

Where is EC available?

  • Progestin-only EC (Plan B One-Step and generics) is sold on shelves at pharmacies without age or gender restrictions. Anyone of any age can buy it and no one should be asked for ID.
  • Ulipristal acetate EC (ella) is prescription-only – users need to see a healthcare provider or go to a clinic for a prescription. 
  • Both types of EC pills can be ordered through online services such as Pandia Health,* Nurx, or Planned Parenthood Direct.
  • Progestin-only EC has been approved for OTC sale since 2014, but it’s not always easy to get. Some stores still keep it behind the counter or ask for ID, even though that’s no longer required.

Why does access matter?

  • EC provides a last chance to prevent pregnancy after unprotected sex, coerced sex, or sexual assault.
  • The sooner EC is taken, the more likely it is to work.
  • Sexual violence on campus is common and often unreported.
  • EC is an important way for students to maintain bodily autonomy and prevent unwanted pregnancy. Students deserve timely access and privacy when seeking EC.

What are some barriers to getting EC?

Progestin-only EC (Plan B One-Step and generics such as Aftera) is approved for over-the-counter (OTC) sale, but access is not always easy: 

  • Not all campus health centers offer EC
  • Health center and pharmacy hours may be limited, especially on nights and weekends, when people may need EC the most
  • Students may have difficulty getting to a local pharmacy
  • Pharmacy prices are high ($40-50)
  • EC is not always stocked directly on the shelf - people buying EC may need to ask pharmacy staff for it, which can feel like a violation of privacy
  • Some pharmacies still ask for proof of ID, based on outdated age restrictions

How effective is EC?

Exact effectiveness rates are hard to calculate for EC pills, because it’s difficult to know the risk of pregnancy for a particular act of intercourse. Here are some things to know about EC effectiveness:

  • The copper IUD is by far the most effective option, followed by ulipristal acetate (ella - the prescription-only pill) and progestin-only EC (Plan B - the OTC pill).
  • EC pills are an important option that should be available to everyone, but both types are less effective than regular contraceptives. 
  • Check out this chart from Bedsider comparing the effectiveness of different types of EC

does a person's weight impact the effectiveness of ec?

Some research shows that EC pills may be less effective depending on your weight or body mass index (BMI). 

  • If you weigh 165 lbs or more (or have BMI of 26 or more), progestin-only EC may not work. In this case, ella (prescription-only EC) or a copper IUD may be a better choice.  
  • If you weigh 195 lbs or more (or have BMI of 35 or more) ella may not work. In this case, a copper IUD may be a better choice.
  • Read more about the research behind EC effectiveness and weight here.
  • Ella is a more effective option for nearly everyone because it works closer to the time of ovulation. If you want to use ella, see your healthcare provider or visit an online provider that can prescribe and/or deliver EC, such as Pandia HealthNurx, or Planned Parenthood Direct.