Vegetarian diet gives advantage in Pregnancy..Yes ?or No?

In oldendays most of the people advice vegetarian diet for pregnant ladies
But Recent studies are mentioning pregnants should take more essential fatty acids ,essential amino acids.As vegerians get less essential aminoacids and fatty acids compared to mixed diet eaters.B12 vitamine also exclusively available in animal products.It couldnot get through pure vegetarian diet.Defiency of B12 leads to megaloblastic anemia.
Conclusion:
Mixed diet is always best during pregnancy to get all types of nutritive things.