- Although it it not a good idea to take birth control pills after you find out you're pregnant, the pills--even in large doses--cannot cause a miscarriage.
- Because large doses of birth control pills can sometimes function as emergency contraception when taken within a few days of unprotected intercourse, many people incorrectly think birth control pills can induce a miscarriage. But by the time you are able to get a positive result on a home pregnancy test, emergency contraception will not have any effect.
- Birth control pills usually work by preventing ovulation from taking place, and sometimes by preventing implantation, and they accomplish this by changing the body's hormone levels to mimic pregnancy. Once you have become pregnant, adding additional hormones to your body could theoretically have negative side effects, but it will not end your pregnancy.
- Large doses of birth control pills used as emergency contraception may stop ovulation or make the uterus inhospitable to implantation, but this will have no impact on an already-implanted zygote. If you had unprotected sex in the past two or three days, check with a pharmacist or doctor before using large doses of birth control pills as emergency contraception.
- A widely reported 2008 study claimed that birth control pills might increase the risk of miscarriage by causing women to pick partners with genetic similarity to themselves, but this was speculation rather than a solid finding of the study. No study has found credible evidence that birth control pills increase the risk of miscarriage even in future pregnancies after stopping the pills.
- If you become pregnant while taking birth control pills, stop taking them. You must either make arrangements to begin prenatal care and proceed with the pregnancy or look into options for dealing with an unwanted pregnancy.
