I'm veggie and was through the whole pregnancy and now BFing. My little boy is very healthy and was born at 4.3kg. As Rosehip said- plenty of Indian mums are veggie and BF and as my H says they have the smartest mathematicians in the the world
If you have a good diet and take extra omega I couldn't see a problem. I take flaxseed oil too as well as a multivitiam. I was taking iron after the birth as I lost blood and was anemic but all is fine there now.