Morning-After Pill: How it Works, How to Take & Other FAQ

Updated in April 2023

The morning-after pill is an emergency contraception option that can be used after sex when another contraceptive method has failed or has not been adequately performed. It can be used, for example, if a condom breaks, or if a woman forgets to take her birth control pill and participates in penetrative sex.

This pill is made up of levonorgestrel or ulipristal acetate, which work by delaying or inhibiting ovulation. 

Pills that contain levonorgestrel can be used up to 3 days after sex, while the pills containing ulipristal acetate can be used up to 5 days after sex. However, these pills‘ efficacy decreases for each day that passes, and therefore should be taken as soon as possible. They can be obtained at the pharmacy without a prescription. 

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How it works

The morning-after pill works by blocking or delaying ovulation. It makes it difficult for the spermatozoid to enter de uterus and fertilize the oocyte. These medications can also alter hormonal levels after ovulation.

Emergency oral contraception will not have any effect after implantation has already occurred, and will not interrupt a pregnancy that is already established, therefore it does not cause abortion or miscarriage. 

When and how to take it

The morning-after pill should be used in emergency cases, anytime there is a risk of an unwanted pregnant. It can be taken in situations like: 

  • Sex without a condom or if a condom rips.
  • Forgetting to take your birth control pill, especially if more than one dose in the same pack is not taken. 
  • IUD expulsion 
  • Dislodging or removal of a vaginal diaphragm 
  • Cases of sexual violence

To prevent pregnancy, the morning-after pill should be taken as soon as possible, after unprotected sex or if other regular contraceptive measures have failed. 

This pill can be taken at any time of the menstrual cycle, and can be taken with water or food. Each box contains one or two pills, to be taken as a one-time dose. 

Side effects

After taking the morning-after pill, women may notice headaches, nausea, and fatigue. Other symptoms can be noted within a few days, such as: 

  • Breast soreness
  • Diarrhea
  • Scant vaginal bleeding
  • Early or delayed period, which can be irregular for some time

Ideally, you should monitor these symptoms and record them on a calender to report to your gynecologist if they persist. Read more about the side effects of the morning-after pill and what you can do to relieve symptoms. 

9 FAQ about the morning-after pill

Many women have doubts about taking the morning-after pill. Some of the most commonly-asked questions include: 

1. Can I still get pregnant after taking the morning-after pill? 

Although it is indicated to prevent unwanted pregnancy, the morning-after pill is not 100% effective if it is taken more than 72 hours after unprotected sex. If it is taken on the same day of sex, the risk of pregnancy is very low, but still possible. 

It is best to wait until your period is expected to come to be sure. You can purchase a pregnancy test from the pharmacy when your period is due. Assess your chances of being pregnancy based on your symptoms  below: 

2. Can the morning-after pill delay my period? 

One of the possible side effects of the morning-after pill is a change to the menstrual cycle. After taking the pill, menstruation may occur up to 10 days before or after the expected date. In most cases, however, menstruation occurs when expected with a variation in 3 or less days. If it is delayed, you are advised to complete a pregnancy test. 

3. Does the morning-after pill cause an abortion? How does it work? 

The morning-after bill does not induce an abortion as it works in different ways, depending on what point you are at in your cycle. It works by:

  • Blocking or delay ovulation, which prevents fertilization of the egg by the spermatozoid. 
  • Increasing the viscosity of vaginal mucus, which makes it more difficult for the spermatozoid to reach the egg. 

Once ovulation has occurred, or if the egg has already been fertilized, the eff will not block pregnancy. 

4. How many times can I take it?

This pill should only be taken sporadically, as it has a very high hormonal dose. The morning-after pill can also lose its effect if taken more than once per month. Therefore, this medication is only indicated for emergency situations and not as a regular contraceptive method. 

5. Is the morning-after pill bad for you?

This pill can be harmful if taken more than twice in the same month. It can increase the risk for conditions like breast cancer, uterine cancer, infertility, thrombosis or pulmonary embolism. 

6. Can the morning-after pill cause infertility?

There is no study that shows that sporadically taking the morning after pill causes infertility, fetal malformation or ectopic pregnancy. 

7. Can the morning-after pill interfere with other contraceptive methods?

No, which is why you should continue to take your birth control pills as normal. Once you reach the end of your pack, your period should still start. If not, see your gynecologist. 

8. Will the morning-after pill work during a woman’s fertile period? 

The morning-after pill will work on any day of the menstrual cycle, although its effect may be slightly lowered during the fertile period (especially if ovulation has already occurred when the pill is taken). 

This occurs because the morning-after pill acts by blocking or delaying ovulation. If ovulation has already occurred, the pill will not have this effect. Nonetheless, the morning-after pill will prevent the spermatozoid from reaching the egg by making the cervical mucus difficult to penetrate. 

9. Does the morning after pill work if I have unprotected sex after taking it? 

No. The morning-after pill is not a contraceptive method and should only be taken in emergency situations. If you take the morning after-pill for an emergency situation and then have unprotected sex the next day, the risk for pregnancy remains. 

Ideally, women should speak to their gynecologists about the contraceptive methods available. 

The morning-after pill is effective when ovulation has not yet occurred, during the first days of the fertile period.