Can woman who are not pregnant take prenatal pill? And how will it affect them?

Prenatal vitamins. Women who are not pregnant are the perfect patient for taking prenatal vitamins because it is important to keep the nutrients in your body that assist with healthy development of a fetus prior to getting pregnant. Sometimes you might get nausea from taking a vitamin but it is important to take them if you are trying to get pregnant.
Vitamin? If you are speaking of a prenatal vitamin, then you have no worry unless you have an iron storage disease or some other contraindication to iron or vitamins. Prenatal vitamins are good vitamins and used by many who are not pregnant. Don't over-vitamin-ate yourself however.