In my opinion prenatal vitamins (PNVs) are less important in the first world, than in areas where fresh fruits and vegetables are not available, or when a blanched diet is not consumed. In a country like Canada, the most important component of prenatal vitamins is the folic acid. Folic acid prevents defects in spine and nervous system development. It is found in abundance in green and leafy vegetables. Deficiency and the resultant developmental problems like spina bifida, an incompletely developed spinal cord, can occur before a woman knows she is pregnant which is why some contraceptive pill makers include folic acid in the blank pills. It also is added to many cereals, breads and other foods as a public health measure. PNVs don t require one to be for or against. Side effects are relatively minor. Some contain iron which helps make extra blood needed in pregnancy, but can cause constipation. B vits, esp 6 can cause mild fatigue but helps in fetal development and to decrease morning sickness. Some people may be sensitive to binders like lactose, a milk sugar some have difficulty digesting. That does not mean they are harmful. Risks are far outweighed by benefit, especially folic acid if taken early. I encourage all reproductive age women to eat healthy, use reliable contraception if pregnancy isn t desired and to take folic acid daily if not utilized.