What is the best Prenatal Vitamin to take while pregnant?

I'm looking to buy my gf a new prenatal vitamin that has dha and possibly omega 3's in it and am trying to figure out what the best one is. I can't seem to find reviews of specific products, instead I'm just finding suggestions for what should be in the vitamin. The doctor just gave her some generic prenatal and we want to find something a little more complete. Any suggestions would be awesome.