Taking birth control pills after unprotected intercourse

Q: What happens if you take a birth control pill after unprotected?

If you take the pill within 72 hours after youve 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.

Overview

The morning-after pill is a type of emergency birth control (contraception). Emergency contraception is used to prevent pregnancy for women who've had unprotected sex or whose birth control method has failed.

Table of Contents Show

Why it's done
From Mayo Clinic to your inbox
How you prepare
What you can expect
What happens if you take a birth control pill after unprotected?
When should you take contraceptive pills after intercourse?
Can I take trust pills after unprotected intercourse?
Will birth control pills be effective immediately after the person takes it?

The morning-after pill is intended for backup contraception only, not as a primary method of birth control. Morning-after pills contain either levonorgestrel (Plan B One-Step) or ulipristal acetate (ella).

Levonorgestrel is available over-the-counter without a prescription; ulipristal acetate is available only with a prescription.

Why it's done

Morning-after pills can help prevent pregnancy if you've had unprotected sex — either because you didn't use birth control, you missed a birth control pill, you were sexually assaulted or your method of birth control failed.

Morning-after pills do not end a pregnancy that has implanted. They work primarily by delaying or preventing ovulation.

Keep in mind that the morning-after pill isn't the same as mifepristone (Mifeprex), also known as RU-486 or the abortion pill. This drug terminates an established pregnancy — one in which the fertilized egg has attached to the uterine wall and has begun to develop.

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Risks

Emergency contraception is an effective option for preventing pregnancy after unprotected sex, but it isn't as effective as other methods of contraception and isn't recommended for routine use. Also, the morning-after pill can fail even with correct use, and it offers no protection against sexually transmitted infections.

The morning-after pill isn't appropriate for everyone. Don't take a morning-after pill if:

You're allergic to any component of the morning-after pill
You're taking certain medications that can decrease the effectiveness of the morning-after pill, such as barbiturates or St. John's wort

If you're overweight or obese, there's some indication that the morning-after pill won't be as effective in preventing pregnancy as it is for women who aren't overweight.

Also, make sure you're not pregnant before using ulipristal. The effects of ulipristal on a developing baby are unknown. If you're breast-feeding, ulipristal isn't recommended.

Side effects of the morning-after pill, which typically last only a few days, might include:

Nausea or vomiting
Dizziness
Fatigue
Headache
Breast tenderness
Bleeding between periods or heavier menstrual bleeding
Lower abdominal pain or cramps

How you prepare

For maximum effectiveness, emergency contraception should be started as soon as possible after unprotected intercourse, and within 120 hours. You can take emergency contraceptive pills anytime during your menstrual cycle.

What you can expect

To use the morning-after pill:

Follow the morning-after pill's instructions. If you use Plan B One-Step, take one Plan B One-Step pill as soon as possible and less than 72 hours after unprotected sex. If you use ella, take one ella pill as soon as possible and less than 120 hours after unprotected sex.
If you vomit within two hours after taking the morning-after pill, ask your health care provider if you should take another dose.
Don't have sex until you start another method of birth control. The morning-after pill doesn't offer lasting protection from pregnancy. If you have unprotected sex in the days and weeks after taking the morning-after pill, you're at risk of becoming pregnant. Be sure to begin using or resume use of birth control.

Using the morning-after pill may delay your period by up to one week. If you don't get your period within three to four weeks of taking the morning-after pill, take a pregnancy test.

Normally, you don't need to contact your health care provider after using the morning-after pill. However, if you have bleeding or spotting that lasts longer than a week or develop severe lower abdominal pain three to five weeks after taking the morning-after pill, contact him or her. These can indicate a miscarriage or that the fertilized egg has implanted outside the uterus, usually in a fallopian tube (ectopic pregnancy).

What happens if you take a birth control pill after unprotected?

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.

When should you take contraceptive pills after intercourse?

Take the first one as soon as possible. Take the second one 12 hours later. The first dose must be taken within 72 hours (three days) after unprotected sex (it could be five days according to your doctor's prescription). The sooner you take the ECP, the better it will work.

Can I take trust pills after unprotected intercourse?

Take the first dose as soon as you can after having unprotected sex, preferably in the first 24 hours, but no later than 72 hours (3 days) after the event. You MUST take the second dose 12 hours after you take the first dose.

Will birth control pills be effective immediately after the person takes it?

How soon does the pill work? It can take up to seven days for the pill to become effective in preventing pregnancy. During this time, you should use another form of birth control. If the pill is used to control symptoms such as acne or abnormal bleeding, it can take three to four months to see true benefits.