Abortion is a procedure to terminate a pregnancy. Birth control and emergency contraception do not end a pregnancy — they prevent a pregnancy from occurring in the first place.

Birth control pills and emergency contraception are commonly confused for abortion medication.

Medically speaking, the chemicals in birth control pills and emergency contraceptive pills are not the same as abortion medication. Additionally, these medications are not used to terminate a pregnancy.

Although birth control pills can be used as a last-resort emergency contraceptive (known as the Yuzpe method), they can’t be used as an abortion medication alternative.

Many people have different personal views on what stage “conception” happens at. But the science is clear that all methods of nonhormonal and hormonal birth control are a means of preventing pregnancy, not terminating pregnancy.

Different kinds of birth control work in different ways. However, no form of contraception is designed to terminate an existing pregnancy.

Many people believe that pregnancy starts at fertilization. As such, they might consider methods that thin the uterine wall (such as the patch and the injection) to be abortion methods, as they stop a fertilized egg from implanting.

Scientifically speaking, pregnancy officially starts when a fertilized egg implants — not when it’s fertilized. This is because implantation signifies the beginning of the fertilized egg developing into an embryo.

Implantation happens about 6–7 days after fertilization, which can occur up to 2 weeks after semen enters the vaginal canal.

Birth control isn’t designed to “kill” a fertilized egg, but it may prevent a fertilized egg from implanting and, therefore, developing in the uterus.

Lifestyle methods

Lifestyle methods of birth control include abstinence and fertility awareness.

In either case, you avoid sexual contact that’s likely to lead to pregnancy.

Barrier methods

Barrier methods involve using a device to block sperm from reaching and fertilizing an egg.

Common examples are:

Hormonal methods

Hormonal contraceptives release small amounts of hormones to reduce the chances of pregnancy. They may:

  • prevent ovulation (i.e., stop your ovaries from releasing an egg)
  • thicken the mucus around your cervix, making it harder for sperm to reach the egg
  • thin the lining of your uterus, which stops a fertilized egg from implanting in the uterine wall

Hormonal methods include:

Surgical methods

Medical procedures — including vasectomy or tubal ligation — prevent fertilization.

Emergency contraception can include pills (which are different from birth control pills) and copper IUDs.

Emergency contraceptive pills

There are two main types of “morning after” pills:

  • levonorgestrel-based pills, available as a generic or branded as Plan B One-Step
  • ulipristal acetate pills (ella)

Levonorgestrel is the synthetic hormone found in birth control pills. Emergency contraceptive pills like Plan B contain a bigger dose of levonorgestrel than birth control pills.

The difference between ella and Plan B is that ella contains ulipristal acetate. But both levonorgestrel and ulipristal acetate prevent ovulation. If an egg isn’t released, there isn’t anything for sperm to fertilize.

Experts have speculated whether levonorgestrel pills prevent implantation after fertilization, but according to a 2014 review, it’s nearly impossible to prove.

Copper IUDs

According to the World Health Organization (WHO), a copper IUD is the most effective form of emergency contraceptive when inserted within 120 hours of sex without a condom or other barrier method.

The copper IUD is a nonhormonal device that works by keeping the sperm away from the egg. Like emergency contraceptive pills, it prevents fertilization.

There are two types of medication abortion:

  • mifepristone/misoprostol combined
  • misoprostol only

Mifepristone stops pregnancy tissue from growing, and misoprostol causes your uterus to shed its lining. Unlike birth control pills and emergency contraception, they end a pregnancy that has already begun.

While misoprostol-only abortions are about 80% effective, the combination of mifepristone/misoprostol is more effective, working 95–99% of the time.

It’s important to note that abortion medication is only used in the early stages of pregnancy. The FDA has approved its use for ending a pregnancy up to 10 weeks.

However, abortion medication is used off-label later than this in some states and in some countries other than the United States.

Lifestyle methods (like abstinence) and barrier methods (like condoms) won’t affect your pregnancy. In fact, condoms can still be used to help prevent sexually transmitted infections (STIs).

A 2016 study found that there’s little evidence that hormonal birth control would harm your pregnancy or cause a miscarriage.

But there’s a lack of research on the matter because of its ethical implications. It would be unethical to have a study where people take birth control pills while pregnant to study the effects on a developing fetus.

If you want to continue your pregnancy, it’s important to stop using hormonal contraception, as it’s unclear how it will affect the embryo or fetus over time.

If you want to end the pregnancy, hormonal contraception will not cause you to miscarry. Instead, make an appointment with a clinic that provides abortions to discuss your options.

If you’re pregnant and would like a tubal ligation, you’ll have to wait until after you give birth or after you have an abortion — whichever choice you make.

What’s the difference between abortion and contraception?

Abortion ends a pregnancy, while contraception prevents pregnancy from occurring in the first place.

Contraception may work by preventing fertilization or preventing implantation.

What’s the argument against birth control?

Many people believe that life begins at fertilization. Because some birth control methods work by preventing a fertilized egg from implanting in the uterus, some people believe this amounts to abortion.

Although the question of when life begins is philosophical and can’t be tested by science, the medical definition of pregnancy is that it begins at implantation, not fertilization.

Thus, birth control methods that prevent implantation are not abortion.

Can birth control of any kind cause infertility?

Hormonal birth control doesn’t cause infertility, according to research. Birth control is designed to delay fertility until you choose to try to conceive.

Of course, surgical birth control methods — including vasectomy and hysterectomy — do permanently affect fertility. Vasectomies can sometimes be reversed, but there’s no guarantee that the reversal procedure will work.

Can abortion of any kind cause infertility?

It’s highly unlikely that an abortion will affect your fertility.

However, outdated and unsafe abortion methods — including abortion procedures carried out by untrained people — pose more risk to your fertility than safe abortion methods.

Birth control is not abortion, and neither is emergency contraception. While birth control and emergency contraception prevent pregnancy, abortions end pregnancy.

Abortion pills are made up of different chemicals than contraception pills. Birth control pills cannot be used to prompt an abortion.

If you’re pregnant and don’t want to be, there are safe and effective options out there.

Learn more at the following links:

Sian Ferguson is a freelance health and cannabis writer based in Cape Town, South Africa. She’s passionate about empowering readers to take care of their mental and physical health through science-based, empathetically delivered information.