Is the morning after pill abortion?

Morning after pills are often confused with abortion pills, but they are two completely different types of pills.

The morning after pill is a form of emergency contraception that should be taken within 120 hours (ideally within 24 hours) after intercourse to prevent pregnancy. The longer you wait the less effective it will be.
Abortion pills are used to terminate a determined pregnancy and can be used until the 8th week of pregnancy.

In the United States, the .S. Food and Drug Administration has approved one type of morning after pill. This pill contains levonorgestrel, and is commonly known under the bran name Plan B. When you purchase Plan B, you will get two pills. Each pill contains 0.75 milligrams of levonorgestrel. The first pill is to be taken as soon as possible; the second pill should be taken 12 hours after the first pill.

In most cases, levonorgestrel will prevent an egg from being released. When no egg is released, no pregnancy can occur.
In cases where the levonorgestrel isn’t capable of preventing the egg from being released, it is usually still potent enough to disrupt the natural hormonal cycle enough to delay the release of the egg. When the release is delayed, the sperms will have time to die and there will be no sperms around to fertilize the egg once it is released.
Levonorgestrel is capable of preventing a fertilized egg from implanting by making the uterine lining less receptive. When this happens, some people view the morning after pill as an abortion, since it prevents a fertilized egg from implanting.
Levonorgestrel is not effective when the fertilized egg has been implanted. This is why it is so important to take the pills soon after intercourse if you want them to be effective. This is also one of the reasons why the morning after pill can not be used to terminate a determined pregnancy; the fertilized egg has already been implanted.