When should pregnant women start iron and calcium supplements?

Before pregnancy: I always recommend taking a good prenatal vitamin containing iron and calcium at least 3 months prior to contemplating pregnancy. Of course life doesn't always work out like we plan but if you can plan a pregnancy start supplementation early.

Prenatal vitamins: You should already be on a prenatal vitamin. Your obgyn will monitor your bloodwork during your pregnancy and make recommendations if you require additional iron and calcium supplementation.