How effective is the morning after pill?

26th November 2019

The morning-after pill is a type of emergency birth control. It is used to prevent pregnancy for women who have had unprotected sex, or where birth control hasn't worked as anticipated. It is only intended as a backup method of contraceptive and should not be used as your primary method of birth control (such as condoms).

If you take the morning after pill within 72 hours after having unprotected sex, the risk of pregnancy is reduced by up to 89%. While this is a high percentage rate, it is not as high as conventional contraception. It is far better to use other methods to prevent unwanted pregnancy if you have the option to do so.

Can the morning after pill cause miscarriage?

No, the morning after pill will not cause a miscarriage. The goal of the morning-after pill is to prevent pregnancy from beginning. After you are already pregnant, the morning after pill will no longer be of use in preventing pregnancy.

How long after having sex can you take the morning after pill?

The morning after pill can be effective for up to five days after sex, or 120 hours. However, the sooner you take the medication, the better it will work. Do not wait until the "morning after" if you have the option to take the medication immediately.

In a study of women taking the morning after pill, separated into two groups (from less than 72 hours in one group, and 72 to 120 hours in another group) the effectiveness was determined to be 87% to 90% in the group who took the pill in less than 72 hours, and 72% to 87% in the group that took it from 72 to 120 hours. The morning after pill is considered to be more effective the earlier it is taken.

Does the morning after pill always work?

The morning after pill doesn't work the same every day of the month. There are some days during the month where the pill will do little or nothing. This pill works by delaying ovulation. By delaying ovulation, the sperm (which can live up to five days in the body after having sex) will die before they are given a chance to find the egg.

However, if the release of an egg is imminent or has already just happened, the morning after pill will do nothing to prevent pregnancy. If you had just released an egg immediately prior to having sex, and then took the morning after pill 10 seconds after having sex, you have the exact same chances of having a baby as if you hadn't taken the pill at all.

What are the names of the morning after pills?

There are two medications that we sell here at UK Meds that are classified as a "morning-after pill". One is ellaOne which sells for £23.49, and the other is Levonorgestrel which sells for £16.99.

Which is more effective, ellaOne or Levonorgestrel?

Both types of emergency contraception are effective at preventing pregnancy if they are used soon after unprotected sex. ellaOne is considered more effective than Levonorgestrel.

It's thought ellaOne is, on average, more effective than Levonelle. ... A 2017 review of the evidence estimated that around 1 to 2% of women who take ellaOne after unprotected sex will become pregnant. In comparison, it's estimated that 0.6 to 2.6% of women who take Levonelle after unprotected sex will become pregnant.

Both pills are less effective with a higher BMI (Body Mass Index)

If a woman has a higher BMI, Levonelle or ellaOne may not be as effective.

The effectiveness of both Levonelle or ellaOne may be reduced if a woman has a high body mass index (BMI). This makes it harder to provide a more precise estimate for either pill.

Does the morning after pill cause abortion?

No, it does not. The morning after pill prevents pregnancy by preventing an egg from being released for up to five days, allowing any sperm released within the body to die off before having a chance to impregnate the egg. If an egg has already been released (prior to taking the morning after pill), a pregnancy will not be prevented any more than if you had never taken the pill.

Can the morning after pill harm a fetus?

No. There are no birth defects associated with taking the morning after pill. There is no risk to a baby if you have already become pregnant.

No, emergency contraceptive pills ("morning-after pills" or "day after pills") do not appear to cause any birth defects. Although no reliable studies have looked specifically at women who gave birth after using emergency contraception, strong reasons exist for concluding that emergency contraceptive pills will not harm a developing fetus.

What is the difference between Levonelle and ellaOne?

There are differences between these two morning-after pills, as noted below.


Levonelle contains levonorgestrel which is a synthetic chemical similar to the natural hormone progesterone. Progesterone is associated with ovulation and preparing the ovary for a fertilized egg.

It’s not known exactly how Levonelle works, but it is believed to work by preventing or delaying ovulation. It will not interfere with your regular method of contraception.


ellaOne contains a chemical called "ulipristal acetate". It stops progesterone from working as it normally would. It can prevent pregnancy by preventing or delaying ovulation.