How Long Do I Have To Take Plan B

How Long Do I Have To Take Plan B

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Angle down icon
An icon in the shape of an angle pointing down.

Home

Chevron icon
It indicates an expandable section or menu, or sometimes previous / next navigation options.

Health

By

Ashley Laderer

Twitter icon
A stylized bird with an open mouth, tweeting.

Twitter

Snapchat icon
A ghost.

Snapchat

Fliboard icon
A stylized letter F.

Flipboard

Pinterest icon
The letter "P" styled to look like a thumbtack pin.

Pinterest

Link icon
An image of a chain link. It symobilizes a website link url.

Copy Link

This article was medically reviewed by Lauren Demosthenes, MD, OB-GYN, senior medical director at Babyscripts .

Our stories are reviewed by medical professionals to ensure you get the most accurate and useful information about your health and wellness. For more information, visit our medical review board.

Ashley Laderer is a freelance writer from New York who specializes in health and wellness. Follow her on Twitter @ashladerer

HEALTH

7 important things to know before taking Plan B, according to OB-GYNs

HEALTH

Common Plan B side effects and what to expect after you've taken it

HEALTH

Does Plan B expire? Yes, and it may be less effective if you take it

HEALTH

Bleeding after Plan B: When it's normal and when it's an early pregnancy sign

Reference Library
Reproductive Health

Chevron icon
It indicates an expandable section or menu, or sometimes previous / next navigation options.

Close icon
Two crossed lines that form an 'X'. It indicates a way to close an interaction, or dismiss a notification.

Plan B, commonly known as "the morning-after pill," can effectively prevent you from becoming pregnant, but only if you take it at the right time.
And while there's no limit to how many times you can take Plan B, that doesn't mean you should treat it like a standard birth control pill that you take regularly.
The sooner you take Plan B after unprotected sex, the better. "The efficacy of Plan B is the best when you take it within 12 hours , and it goes down from there," says Nichole Butler, MD, board-certified OB-GYN at Weiss Memorial Hospital's Women's Health Center . You can take Plan B up to 72 hours after unprotected sex. However, the pill's effectiveness at preventing pregnancy dwindles the later you take it:
It only takes a couple of hours for Plan B to kick into effect, says Butler. A 2018 review found that peak levels of levonorgestrel (the active ingredient in Plan B) in your blood will typically be around 1.7 hours after taking the pill.
Note : If you weigh 155 pounds or more, you should opt for another kind of emergency contraception pill called Ella . Ella can be used up to 120 hours after unprotected sex, though it's more effective the sooner you take it.
You only need one dose for each episode of unprotected sex. "Taking more than one dose of Plan B after one episode of unprotected sex is not going to make a difference in its effectiveness," says Aparna Sridhar, MD , an OB-GYN at UCLA Health.
But there are some exceptions to this rule, like:
That said, Sridhar also advises against taking Plan B multiple times a week. While it's not technically dangerous to your health, you may experience short-term side effects like headache, fatigue, nausea, and temporary changes in your menstrual cycle.
Moreover, if you find yourself in the situation where you're taking Plan B multiple times a week, you should strongly consider going on

birth control

regularly for a couple of reasons:
If you wait multiple days to take Plan B, chances of preventing pregnancy aren't great.
A 2011 meta-analysis found that taking emergency contraception on the fifth day (120 hours) after unprotected sex makes you five times more likely to get pregnant than if you took it within 24 hours.
Waiting five days increases the odds that you ovulated in that time period, and therefore, there's a chance that a sperm may have already been able to fertilize a released egg, Butler says.
Furthermore, sperm are able to live inside your body for up to a maximum of five days . The bottom line is, waiting five days after unprotected sex to take Plan B is leaving a lot up to chance. "At 120 hours, you're really crossing your fingers," says Butler.
Additionally, taking Plan B will not harm or terminate an existing pregnancy, Butler says, and it does not act as an abortion pill. "If there is an embryo implanted in the lining [of the uterus], there is nothing that Plan B is going to do to prohibit that. It's already happened," says Butler.
The main way plan B works to prevent pregnancy is to delay ovulation. It cannot stop the ovulation process if it's already started. Therefore, if you take plan B a day or two after you've started ovulating, it will be less effective.
How much less effective is unclear but according to one small 2011 study :
It can be tricky to know if you've already ovulated or not if this isn't something you typically track. Ovulation happens about a week after the last day of your period and you might experience symptoms like:
Despite being less effective if you've just ovulated, plan B also thins the uterine lining. So even if you have recently ovulated, you should still take it since your chances are better at preventing pregnancy than if you don't take it, Butler says.
Note: You can also consider a copper IUD, though you will need to schedule a doctor's appointment to get one. The copper IUD may be more effective at preventing pregnancy during or right after ovulation, since it may prevent implantation, even if fertilization has occurred.
Plan B can be very effective at preventing pregnancy if you take it within 72 hours of unprotected sex, and preferably even sooner.
While you can take Plan B multiple times, it is meant to be emergency contraception and not a replacement for birth control.
If you find yourself using Plan B often, talk to your gynecologist about long-term contraception options.

All

Select the section you want to search in

All
Consumer
Professional
Pill ID
Interactions
News
FDA Alerts
Approvals
Pipeline
Clinical Trials
Care Notes
Natural Products

Browse all medications:

a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
0-9

Advanced Search

Medical Answers
How effective is Plan B and how late can you take it?

I accept the Terms and Privacy Policy

Select one or more newsletters to continue.

Ad Choices

We comply with the HONcode standard for trustworthy health information.

Copyright © 2000-2022 Drugs.com. All rights reserved.

Medically reviewed by Sally Chao, MD . Last updated on July 30, 2021.
Plan B ( levonorgestrel ) is estimated to be 60% to 94% effective at preventing pregnancy when taken within 3 days (72 hours) after unprotected sex. Somewhere between 0.6% to 2.6% of women who take Plan B within this time frame will still become pregnant.
While Plan B can be taken up to 72 hours after unprotected sex, its efficacy decreases with time, and it is best to take it as soon as possible. For example, the chances of pregnancy are higher if Plan B is taken 4 days after unprotected sex, but are subsequently lowered if taken 3 days, 2 days, 1 day or within 24 hours after unprotected sex. However, the American College of Obstetricians and Gynecologists notes that some studies suggest that it can be moderately effective at preventing pregnancy up to 5 days after unprotected sex. Five days after unprotected sex is the latest time with which Plan B has been shown to lower your chances of pregnancy.
The efficacy of Plan B is also affected by the time at which it is taken within your menstrual or reproductive cycle. Plan B works best when taken before ovulation, or when an ovary releases an egg. Once there is a surge in the hormone that initiates ovulation and ovulation begins, Plan B cannot prevent pregnancy. Its primary mechanism of action is to change hormone levels such that ovulation is delayed. This is why it is important to take Plan B as soon as possible after unprotected sex. As treatment is delayed, ovulation becomes more imminent (if it has not yet occurred).
A review of studies in Clinical Obstetrics and Gynecology showed that among 492 women who took Plan B after unprotected sex, those who took it on or after the day of ovulation had the same pregnancy rate as would be expected among women who used no contraception at all. By comparison, none of the women who took Plan B before ovulation became pregnant.
In the event of another unprotected sexual encounter after Plan B is taken, Plan B will not protect against pregnancy—you will need to take Plan B again after another unprotected sexual encounter.
Plan B may also be less effective at preventing pregnancy in women who are overweight or obese. Studies reviewed by Cochrane suggest that the dose of levonorgestrel in Plan B has a lowered potency when taken by women who have a higher body mass index.
The easiest way to lookup drug information, identify pills, check interactions and set up your own personal medication records. Available for Android and iOS devices.
Subscribe to Drugs.com newsletters for the latest medication news, new drug approvals, alerts and updates.
Drugs.com provides accurate and independent information on more than 24,000 prescription drugs, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. Data sources include IBM Watson Micromedex (updated 5 July 2022), Cerner Multum™ (updated 27 June 2022), ASHP (updated 16 May 2022) and others.
Help support Drugs.com by allowing ads...

Medically Reviewed by Brunilda Nazario, MD on April 17, 2020
Levonorgestrel is a hormone that can be used for emergency contraception. Emergency contraception should not be used as a routine method of birth control.
Levonorgestrel can prevent pregnancy after unprotected sex. People sometimes call it the "morning after pill." But you don't have to wait until the morning after sex to take it. In fact, levonorgestrel is more effective the sooner you take it. It is a one-dose regimen: you take one pill. The pill contains 1.5 milligrams of levonorgestrel , which is used in lower doses in many birth control pills .
Levonorgestrel brands include Econtra EZ, My Way, Next Choice One Dose, Plan B One Step, Preventeza, and Take Action. These are given as a one pill emergency contraception or as 2 pills taken separately within 72 hours of unprotected sex.
Depending upon where you are in your cycle, levonorgestrel helps prevent pregnancy after unprotected intercourse. It may prevent or delay ovulation .
Levonorgestrel is not the same as RU-486, which is an abortion pill. It does not cause a miscarriage or abortion. It will not work if you are already pregnant when you take it. Learn more about how emergency contraception works .
If you take the pill within 72 hours after you've had unprotected sex, levonorgestrel can reduce the risk of pregnancy by up to 87% if taken as directed. If you take Plan B One-Step within 24 hours, it is much more effective.
But you should know that Plan B One-Step is not as effective as regular contraception . So don't take it as a form of birth control . And, it does not protect you against sexually transmitted diseases. Think of it as a backup -- not for routine use. That's why it's called Plan B. Get more information on emergency contraception and its effectiveness.
Plan B One Step can be purchased over the counter at drugstores without a prescription or proof of age. Because it is most effective when taken as soon as possible (up to 72 hours after unprotected sex), consider having a ready supply in your medicine cabinet. Better yet, use a reliable form of birth control, and plan for a backup method of birth control.
Remember:Plan B will not protect you from getting pr
Babysitting Sex Story
Just Good Porn
Assm Story

How Long Do I Have To Take Plan B

Report Page