Can oral contraceptives cause an abortion?

Dear Reader,

Your question is certainly a common one; many people using hormonal birth control worry that it could cause an early pregnancy loss. The short answer to your question: No, birth control pills won’t abort the fetus. Combination birth control pills — generally made of estrogen and progestin (synthetic progesterone) — prevent pregnancy by inhibiting ovulation and causing the cervical mucus to thicken. After pregnancy begins, it’s unlikely that taking the pill will have any effect on embryonic (an egg fertilized by a sperm) or fetal (after eight weeks when there is a heartbeat and facial features begin to develop) development. 

However, if a pregnant person continues to use a progestin-only contraceptive, sometimes called the minipill, that only contains a synthetic form of the hormone progesterone, there may be an increased chance of having an ectopic pregnancy. This is when the fertilized egg begins to develop outside of the uterus, often in the fallopian tubes, where there isn’t enough room for it to grow. These pregnancies are more likely because the minipill only thickens the cervical mucus, which could cause the embryo to attach outside of the uterus instead. Ectopic pregnancies can be life threatening because they may cause internal bleeding, so they need to be resolved quickly and appropriately. Someone experiencing an ectopic pregnancy may have sharp stabbing pains, cramps, or a dull headache that can become severe, while others may experience significant blood loss and go into shock if a fallopian tube bursts. If experiencing any of these symptoms, seek medical care immediately.

On the other hand, there are specific medications designed to prevent a pregnancy when other birth control methods fail. For example, the one-dose pill levonorgestrel (commonly known as Plan B and its generic forms) is one such emergency contraception method, which is most effective if used within 72 hours and decreases the chance of pregnancy, especially if taken right away. It stops the sperm from implanting into the egg, which blocks the development of an embryo. It will not end a pregnancy where the egg has already implanted. Another common form of emergency contraception is the copper intrauterine device. For more on Plan B or other alternatives, consider checking out the Q&A about where to find basic information about emergency contraception. 

There are also medications that can be taken to intentionally end a pregnancy. In the United States, mifepristone is used to block the hormones that are needed to maintain a pregnancy. Misoprostol may also be used, alone or in combination with another medication, to contract the uterus, causing the uterus to flush out the egg. Methotrexate is another drug that stops a pregnancy from developing further. Taking any of these pills induces an abortion, ending the pregnancy. This type of abortion, also known as a medical or medication abortion, must be supervised by a health care professional within 70 days of the last period and is an alternative to having a surgical abortion. None of these are considered birth control and can't be used to prevent a pregnancy, so birth control methods, such as condoms or other barrier methods, or oral contraception, are needed following an abortion to prevent unwanted pregnancy. 

If you're a pregnant person looking for options or want to discuss birth control methods that are right for you, it’s best to speak with your health care provider. They can help you figure out which methods may be best for you, or if you're looking to end a pregnancy, which options of pregnancy termination will best suit your health needs.