Plan B Emergency Contraception: Where to Get It, Purchase Limits, Effectiveness

The use of emergency contraception can help prevent pregnancy before it begins. We'll explain how it works and who can use it.

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Katie is a writer covering all things how-to at CNET, with a focus on Social Security and notable events. When she's not writing, she enjoys playing in golf scrambles, practicing yoga and spending time on the lake.
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Katie Teague
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Plan B One-Step box

Plan B One-Step is available over the counter.


It happens to many women: You had a busy day and accidentally missed a dose of your birth control. But what happens if you have unprotected sex after you've missed a pill? Fortunately, there are emergency contraceptives, like Plan B, which have been shown to be an effective way to prevent unwanted pregnancies when your birth control method fails -- or if you don't use one at all.

Now that Roe v. Wade has been overturned, ending the constitutional right to an abortion, you may be wondering if you can still get the pill. The answer is yes. However, due to increased demand, stores like Amazon and Rite Aid are limiting how many can be purchased at a time to three pills per customer, CNN reported.

Let's get one thing straight right off the bat: Plan B isn't an abortion pill. It can't end a current pregnancy. What it can do is prevent a pregnancy from happening at all.

We'll explain how Plan B works, when you should (and shouldn't) take it and how to get it. 

What is the Plan B pill?

Plan B is one brand name for levonorgestrel, a synthetic form of the hormone progestin, which temporarily delays ovulation (when an egg is released from the ovary). By delaying ovulation, the pill keeps sperm from fertilizing an egg and thus prevents pregnancy after unprotected sex. The pill's effect is only temporary and won't prevent you from getting pregnant in the future, according to Plan B One-Step's website.

It's an over-the-counter emergency contraceptive pill that's also called the "morning-after pill" because people often take it the day after having unprotected sex. 

Note that Plan B is often used as a catchall term for emergency contraception, but there are emergency contraceptive pills other than Plan B, such as Aftera, Take Action, My Choice and Ella. However, Ella requires a prescription and can't be bought over the counter. Ella contains ulipristal acetate, a progesterone agonist that temporarily delays ovulation and can be taken up to five days after unprotected sex. It's also said to work better than Plan B for those who weigh more than 165 pounds.

How soon should you take Plan B after unprotected sex?

If you had sex and didn't use birth control, including pills or condoms, it's recommended that you take Plan B within 72 hours. The sooner you can take it, the better it works. 

You can also take it to prevent an unplanned pregnancy if you missed a dose of your birth control pill or if there was an issue with the form of birth control you used -- if, for instance, the condom broke.

You can use Plan B's countdown calculator to determine if you're still in the time frame that it would be effective at preventing pregnancy.

How effective is Plan B?

plan B one step packaging

One package of Plan B comes with one pill.

Plan B One-Step

When Plan B is used within the 72-hour time frame, it can significantly decrease the chances of getting pregnant. Roughly seven out of every eight people -- or nearly 88% -- who could have become pregnant didn't do so after taking it.

"Use this intervention as soon as possible after a sexual relationship in which pregnancy is possible," Dr. Gloria Bachmann, director of the Women's Health Institute at Rutgers University, told CNET.

After 72 hours the effectiveness decreases, although you can take the pill up to five days after unprotected sex.

Also, Plan B may be less effective in people who weigh more than 165 pounds. Other emergency contraception pills, like Ella, may also be less effective for those who weigh 195 pounds or more

Bachmann recommends women who weigh more than 165 pounds ask a health care professional for alternatives if they're concerned that levonorgestrel is less effective for them. 

However, research is unclear on whether or how much weight influences the effectiveness of emergency contraceptives. It's still worth taking a dose if you need one, regardless of your weight.

What Plan B shouldn't be used for

While Plan B is effective in minimizing the chance of becoming pregnant, there are a few things it shouldn't be used for, according to Plan B's manufacturer.

Don't use Plan B in place of your regular birth control because it only stays in your system for a short amount of time. Continue using your regular birth control after taking Plan B.

Don't take Plan B if you are already pregnant. The manufacturer notes that it's not an abortion pill and will not have an effect an existing pregnancy.

Don't use Plan B to try to prevent sexually transmitted diseases. Plan B can only help to prevent pregnancy, so it's best to use barrier methods, like condoms, for preventing STDs.

Where to get a Plan B pill

Plan B is available over the counter in stores and online at major retailers, like CVS, Walgreens, Walmart, Target, Amazon and Rite Aid. You can also buy it from the Plan B website. Note that many stores keep the product behind the pharmacy counter, but you may also find it in front of the pharmacy counter and in the family planning aisle. Also, some stores have a protective casing around the pills that you may need an employee to unlock.

You don't need to show an ID or have a prescription, and you can buy it in advance for a just-in-case situation so you already have it on hand. 

It costs roughly $40 to $50 for one pill, depending on where you buy it. Some insurance plans may cover emergency contraceptives, so we recommend contacting your insurance company for more details. If your plan doesn't cover it, a pharmacist may be able to tell you why.

If you don't have insurance or your plan doesn't cover Plan B, you may be able to get it free or at reduced cost from your local health department, Planned Parenthood or other health clinics.

Why is there a limit on how many pills you can buy?

Purchasing-limits on emergency contraception at stores like Amazon and Rite Aid came after the decision to overturn Roe v. Wade, according to CNN. CVS temporarily placed a limit on emergency contraception but has since removed it. The limit of three per customer is to ensure there's ample supply on store shelves. At this time, there's no known shortage, but we'll update this story as we hear more.

Who can use Plan B?

Anyone who can become pregnant is eligible to take Plan B, regardless of their age. But there's some research that shows it may be less effective for some people.

The Food and Drug Administration said in 2016 that all people who ovulate, regardless of how much they weigh, can use emergency contraceptives like Plan B to prevent pregnancy. However, some CDC studies show that it may not be as effective for people who have a BMI of 30 or higher, or who weigh 165 pounds or more. At this time, there's still not enough research to show if weight impacts the effectiveness of Plan B.

There are medications that can disrupt how well the morning-after pill works, including the antibiotic Rifampin, the antifungal Griseofulvin, some HIV medicines, some anti-seizure medicines and St. John's wort. Bachmann said people who use barbiturates -- depressant drugs prescribed by doctors or purchased illegally -- should not take a levonorgestrel pill.

If you're taking any of those drugs, consult a health care professional before using Plan B.

What are the side effects of Plan B?

Plan B is considered safe to use, but there are some side effects you may experience:

  • Your period could be lighter, heavier, earlier or later than usual
  • Nausea
  • Lower abdominal cramps
  • Tiredness
  • Headache
  • Dizziness
  • Breast tenderness
  • Vomiting -- if this happens within two hours, contact your health care provider to see if another dose is necessary.
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.