why would you do this? it will not make you twice as healthy or make your baby twice as healthy. just take the dosage that is recommended by your ob. you don't need to double it. too much of certain vitamins like a or d (the fat-soluble ones) can be unhealthy (but it is not likely that a double dose of prenatal vitamins would be at this toxic level) and excessive minerals can challenge our liver and kidneys. the body does not store vitamins so any excess amounts of most vitamins would likely be urinated away. don't waste your money or take the risk. allow your ob to make these decisions for you during your pregnancy.
is it harmful to take twice the amount of prenatal vitamins when pregnant?