Can Birth Control Pills Cause a Miscarriage?

The Answer Depends On What You Mean By the Question

woman taking birth control pill
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Many women who experience a pregnancy loss wonder if their birth control could have caused the miscarriage. Some women, on the other hand, wonder if they can terminate a pregnancy with birth control pills. 

The answer to the question of whether birth control pills or other hormonal contraception can cause a miscarriage depends on what you mean by the question.

Can Birth Control Increase Miscarriage Risk?

Birth control pills probably do not increase the risk of miscarriage.

The research is conflicting on this point, but there seems to be more evidence that exposure to hormonal birth control pills does not increase risk of miscarriage than evidence that it does.

  • One 2005 study found that using oral contraceptives for longer than two years led to an increased risk of miscarriage.
  • A 1995 study found that long-term use of hormonal birth control could actually decrease the risk of miscarriage due to chromosomal abnormalities for moms over 30.
  • Another study, published in 2002, found that long-term use of oral contraception was associated with women becoming pregnant faster after deciding to conceive. The researchers also cited past research suggesting that pregnancies after recent pill usage were less likely to end in miscarriage.

What If You Conceived While on the Pill?

When used appropriately, most types of birth control pills are considered more than 99 percent effective at preventing pregnancy.

Yet, sometimes women get pregnant while taking the pill. This can happen if they frequently forget to take the pill, for example, or if they are using medications that decrease the effectiveness of the pill.

There should not be an increased risk of miscarriage or any other problems with a pregnancy due to accidental exposure to hormonal birth control.

A large 2008 study examined a registry of 92,719 women and found no evidence of increased risk of fetal death in babies exposed to artificial hormones during pregnancy.

Still, if you are in this situation and plan to keep the pregnancy, you should obviously stop taking the pill immediately. 

Using the Pill to End a Pregnancy

Finally, if you are facing an unwanted pregnancy, you may have heard that you can take large doses of birth control pills to end the pregnancy. But if you have already confirmed you're pregnant, this strategy is not likely to end your pregnancy. You will need to research other options for unwanted pregnancy.

Technically, it's true that taking a large amount of birth control pills could work for emergency contraception if it's done within a few days after intercourse, but the effective dose would depend on the pill brand. If you are considering emergency contraception within a few days after unprotected intercourse, talk to a physician or pharmacist right away. They can help guide you through this process safely and effectively.

 

But by the time a pregnancy test comes back positive, a large dose of birth control hormones will probably not terminate the pregnancy. 

Sources:

Farrow, A., Hull, M.G.R., Northstone, K., et al. (2002). Prolonged use of oral contraception before a planned pregnancy is associated with a decreased risk of delayed conception. Human Reproduction.

Ford, J.H. and MacCormac, L. (1995). Pregnancy and lifestyle study: the long-term use of the contraceptive pill and the risk of age-related miscarriage. Human Reproduction.

García-Enguídanos, A., Martínez, D., Calle, M., et al. (2003). Long-term use of oral contraceptives increases the risk of miscarriage. Fertility and Sterility.

Jellesen, R., Strandberg-Larsen, K., Jørgensen, T., et al. (2008). Maternal use of oral contraceptives and risk of fetal death. Paediatric and Perinatal Epidemiology..

Which birth control pills can be used for emergency contraception in the United States? Office of Population Research & Association of Reproductive Health Professionals. July 2008.

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