What is the difference in over the counter versus prescription prenatal vitamins?

Prescription prenatal vitamins such as TriCare DHA ONE® with Folate are able to include more of the key ingredient folic acid (necessary for the prevention of neural tube defects such as spina bifida) than over-the-counter prenatals. Also, prescription prenatals are subject to greater FDA oversight than over-the-counter prenatals. Finally, prescription prenatals typically utilize the optimum forms of the ingredients they contain, while this is not always the case for over-the-counter prenatals.