If you forgot to take a birth control pill, you might be worried you are pregnant. But could your birth control pills interfere with your pregnancy test? Birth control pills work by suppressing ovulation with synthetic estrogen and progesterone; however, they do not contain the hormone human chorionic gonadotropin. Pregnancy tests rely on the presence of human chorionic gonadotropin in your body.
Human Chorionic Gonadotropin
Human chorionic gonadotropin, or hCG, is the hormone that indicates you are pregnant. When the fertilized egg implants in the uterus, your body starts producing hCG. The amount of hCG builds in your body each day that you are pregnant, according to the National Women's Health Information Center (NWHIC).
Pregnancy Tests
Two types of pregnancy tests are available--home tests and tests at your doctor's office. Both types of pregnancy examinations test the levels of hCG. Home tests use urine; tests at your doctor's office use either your blood or urine. Blood tests can detect hCG sooner than urine tests can. According to the NWHIC, home tests are effective as long as they are done a few days after your missed period. If done too early, the home test will not pick up enough hCG to come back positive.
Interference
According to both the Mayo Clinic and the NWHIC, birth control pills cannot interfere with a pregnancy test. Since birth control pills do not contain hCG, using them will not result in a false positive. Only medication, like infertility drugs, that contain hCG can result in a false positive. However, if you are planning to get pregnant and take birth control pills, the Mayo Clinic says ovulation may begin 2 weeks after your last pill.
