Birth Control

The Morning After Pill ("Emergency Contraception")

2 min read

What is it?
Products (whether pills or an IUD) that prevent pregnancy after an episode of ‘unprotected intercourse.’ Unprotected sex means both when no birth control was used or it was used imperfectly.  

Emergency contraception (EC) does not interrupt a pregnancy that is already growing inside your uterus or womb. It does not cause an abortion. EC typically works by either preventing your ovary from releasing an egg or stopping the sperm from reaching the egg.

When do I take it?
Emergency contraception is something you should take when you have had unprotected intercourse and want to decrease your chances of becoming pregnant. This includes episodes where no birth control was used or if birth control was used but was not effective. Common examples of this include if a condom slipped/broke or multiple birth control pills were missed. Most forms are effective up to either 72 or 120 hours (3 or 5 days) after intercourse.

It should always be taken as soon as possible after the episode of intercourse as how effective it is can change over time.

What forms are available?
In the US, there are generally three different forms of EC:

Copper IUD (intrauterine device) or Paragard: This is the most effective form of EC, about 99.9% effective. It can be inserted up to 5 days after unprotected intercourse. Not only that, the copper IUD can be left in place for 10-12 years after insertion as birth control and unlike other pills (see below), its effectiveness does not change depending on your weight.

This is a great option for patients who know they want to use the copper IUD as their form of birth control. This method requires a trip to the doctor for insertion. Note, the copper IUD may not be best form of birth control for those who have heavy and painful periods as it can make these conditions worse.

Levonorgestrel Pill [New Day, My Way, Plan B, Next Choice, etc]: This is the over-the-counter morning after pill. It does not have age limitations and does not require a prescription. However, if you have insurance and get a prescription from a doctor, insurance will often cover it at $0 copay. Typically it includes one pill of 1.5mg of levonorgestrel although sometimes it can be split into two pills of 0.75mg each you take 12 hours apart. This method should be taken within 72 hours (or 3 days) from unprotected intercourse. It is important to note is that this pill may be less effective for women who have a higher BMI (which depends on your weight and height). The efficacy starts to decrease with a BMI above 25.

Ullipristal Pill [Ella]: A pill that can be used up to 5 days after unprotected intercourse. This is more effective and can be used longer than levonorgestrel pills but requires a prescription. It does also become less effective the higher your weight, though less so than compared to levonorgestrel. Also, you need to wait 5 days after taking this to start hormonal birth control because this might make ulipristal less effective.

Lastly there is what is known as the Yuzpe method.

The method means combining a number of birth control pills in two doses to get a high enough estrogen dose to prevent yourself from releasing an egg. It only works with certain pill brands (you can find more information here: and it requires taking two doses 12 hours apart. Because of the high estrogen (not found in other EC’s), you can become nauseous with this method and have other side effects like breast tenderness, headaches and spotting. You should take this with food and call a doctor if you vomit within 1 hour of taking them.

This method is not as effective and has more side effects than the other ones, but this is an option if you are not near a pharmacy or cannot get in touch with a physician for access to another EC option.

If I’m already on the pill but miss a day, do I need to take EC?
Typically no but it depends on the type…

For regular combined birth control pills, you should consider using EC if you have missed 3 pills in a row and had intercourse or if you are 3 or more days late in restarting your patch or ring.

If taking the progestogen-only pill or “minipill,” you should consider taking EC if you take your pill even 3 hours late (or take it more than 27 hours from your last pill).

There is a special kind of combined pill that contains a desogestrel, and if you are more than 12 hours late in taking this pill, you may also want to consider taking emergency contraception.

Lastly, if you are more than 4 weeks late for your depot-medroxyprogesterone acetate injection, you are no longer protected and should consider EC if having otherwise unprotected intercourse.

How effective is it?
If taken as directed, these are the typical effectiveness rates:

Copper IUD: 99.9% effective

Levonorgestrel Pill (New Day, My Way, Plan B): 97.4% effective

Ullipristal (Ella): 99.2% effective

Yuzpe Method: Prevents about 75% of pregnancies

Who should I not take it?
The only absolute contraindication in taking EC is if you know you are already pregnant as the pills will no longer work. That said, there are a few things to note.

The levonorgestrel pill is only approved for up to 3 days after unprotected intercourse and in general is less effective than ullipristal or Ella and the copper IUD.

Both ullipristal and levonorgestrel may be impacted by body weight. In particular, levonorgestrel may be more affected by this. Women with a body mass index (calculated using weight and height) over 25mg/m2 may be counseled to use ullipristal instead of levonorgestrel and women with a body mass index over 30mg/m2 may consider using the copper IUD or at least ullipristal over levonorgestrel for best efficacy.

Women with a history of bariatric surgery should talk to a physician as they may be less able to absorb medication taken orally.

How long after taking it do I need to wear condoms (or use a back-up form of contraception)?
See below - but for the oral options it is a minimum of 5 days.

If I am starting birth control, when do I start it after taking EC?
Ullipristal or Ella:
Because Ella works opposite to birth control pills, we recommend waiting at least five days after you take Ella to start birth control. This includes pills, the patch, injection, any hormonal implant or IUD or the ring. As a reminder, you also need to use back-up like a condom for seven days after starting birth control. This means if you take Ella and then start birth control five days later, you should either abstain from sex or use a condom for a total of 12 days (5 days after taking Ella and another 7 days after starting birth control).

Levonorgestrel or Plan B: You can start birth control the same day you take the levonorgestrel and you should use a backup method such as condoms or avoid sex for one week (7 days).

Copper IUD: This serves as emergency birth control and also immediately starts to act as long-term birth control. No waiting period or backup is needed.

Yuzpe Method: You can start pills or any method of contraception after taking the second dose. You should wait one week to have sex or use a back-up method for seven days.

Are there side effects?
The most frequent side effects from the pills are headache and nausea. Most people get their periods within 1 week of when it is typically expected, but some patients may have some irregular bleeding or spotting the month after use. This should go away on its own. Other effects can be breast tenderness, dizziness and fatigue. IUD insertion comes with other possible side effects.

Can I take it twice in one cycle?
Repeated use appears safe and fairly effective, but there can be an increase of bleeding episodes.

Do I need a prescription for them?
The levonorgestrel pill does not require a prescription. However, if you have insurance and get a prescription from a doctor, insurance will often cover it at $0 copay.

Ullipristal and the copper IUD require a prescription or trip to a physician.

Can I keep the pills around ‘just in case’? Do they go bad?
All drugs after expiration dates you should pay attention to but typically these are not for several years so it is okay to keep a dose or two at home in case of an ‘emergency.’

Looking for more personalized info? Message a doctor through Twentyeight to get medical advice based on your needs and lifestyle.

With the participation of
Dr. Alejandra Moscoso

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