Woman's hand holding a Plan B packet with a pink background

Important Things to Know
Before Taking Plan B

By Lizzie De La Cruz
June 8, 2022

It’s always a good idea to have a plan B! If everything went smoothly, Plan B pills would not be necessary, but since anything can happen, including mistakes, the Plan B pill is a good thing to have access to if you need it. Here are some important things to know about this morning after pill, and what you should know before taking Plan B.

What is Plan B?

Plan B is an emergency contraceptive that is easily available over the counter in most drugstores. You don’t need a prescription to purchase Plan B. The active drug in Plan B pills is levonorgestrel, which is a hormone used as an emergency contraceptive. It is not an abortion pill. The Plan B pill primarily works much like the birth control pill— it stops the ovary from releasing an egg and may prevent the sperm from fertilizing the egg if one is released. It does not terminate an embryo that already exists.

The sooner a Plan B pill is taken the better, but one pill is all you need. If the pill is taken within three days of having unprotected sex, your risk of pregnancy drops by 89 percent, and if taken within the first 24 hours, the risk of pregnancy goes down by 95 percent. Take the pill as soon as possible after sex. Even though it is known as the “morning after pill,” it’s not necessary to wait that long to use it. If you can take it immediately after sex, you should!

Are Plan B pills less effective for women weighing over 155 lbs?

Maybe. Levonorgestrel (the generic name of Plan B) might not work as well for women with a BMI greater than 25 or weigh over 155lbs. There are other alternatives, but there is no reason not to consider Plan B pills if they are available. In research trials, the incidence of pregnancy was lower across all BMIs after taking the plan B pill, so don’t assume that it will not work. However, be sure to check with your Wisp doctor about whether Plan B is a good option for you.

Ella is a prescription emergency contraceptive that is more effective than Plan B for those who are between 155 and 195 lbs, or up to a BMI of 30. However, it too is not effective for people who have a BMI of 35 and above and are over 195 lbs. If this is you, talk to your doctor about your emergency contraceptive and birth control options.

Plan B may interrupt your regular cycle

You might notice irregular spotting after taking this pill, a lighter or heavier flow, or a delay of your period for a few days. This is common and nothing to worry about. It just means that it is taking your body a bit longer to return to your regular cycle.

Plan B pills are safe

They will not increase risk of miscarriage or prevent future pregnancies. There are some side effects such as nausea, abdominal pain, fatigue, headache, or dizziness. The pills work as a second method of birth control if your usual birth control fails or was not used (it happens!).

Plan B has a shelf life

Don’t leave your morning after pills in the bathroom cabinet for years until they are needed. Taking it after the expiration date is not dangerous, but the pills will lose their efficacy over time. It is good to have some on hand, but they do expire after about four years.

How much does Plan B cost?

Order Plan B pills in advance so you can take them as soon as accidents happen. With Wisp, you can get a 3-pack of Plan B for just $40, delivered straight to your front door. No trip to the pharmacy, no waiting in line. Keep it in your medicine cabinet for yourself or a friend.

Get Emergency Contraceptives Online

Plan B emergency contraception in foil packet to prevent pregnancy on a red surface, on a pink background

Levonorgestrel (Generic PLAN B®)

Take Levonorgestrel as soon as possible but within 72 hours (3 days) of unprotected intercourse or contraceptive failure. Levonorgestrel (Generic PLAN B®) is delivery only - order ahead of time!

Starting at $18.00

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Ella emergency contraception in foil packet to prevent pregnancy on a red surface, on a pink background

Ella® Emergency Contraception

Take Ella as soon as possible, but within 120 hours (5 days) of unprotected intercourse or contraceptive failure. Ella is pick-up only - order after contraceptive failure!


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NuvaRing birth control on a red surface with a pink background

Vaginal Birth Control Ring (Generic NuvaRing®)

The contraceptive ring (NuvaRing®) protects you from pregnancy without a daily pill.

Starting at $22.00

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The birth control patch on a red surface with a pink background

Birth Control Patch

The Birth Control Patch is non-invasive contraception that makes it easy to prevent pregnancy.

Starting at $12.00

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