A pregnancy test measures the level of human chorionic gonadotropin (hCG) in your blood or urine. This hormone is only produced during pregnancy, so its presence is a good indicator that you are pregnant. However, sometimes vitamins can cause a false-positive pregnancy test.
Vitamins can increase hCG levels in your body and lead to a false-positive pregnancy test. This is most likely to happen with vitamins that contain hCG, like some fertility treatments. If you take vitamins regularly, talk to your doctor about whether they could be affecting your pregnancy test results.