In normal human brain tissue there is a high concentration of Omega-3 fatty acids. This leads researchers to believe that Omega-3s play an important role in the brain function of all healthy adults. But when it comes to developing fetuses, the role is even more crucial. During pregnancy and the first two years of life, the brain accumulates DHA or docosahexaenoic acid, a specific type of Omega-3 fatty acid. Research has shown that babies born to mothers with high blood levels of DHA had advanced attention spans as infants and learn much faster as children.
So the bottom line is if you're pregnant you need at least 250mg of DHA each day. You get some of this from seafood and other food sources (flax seed is another good source), but because it's so vitally important to your baby's brain development that you get enough, you should take a supplement in addition to pre-natal vitamins. As always consult with your doctor before taking any new supplements, especially during pregnancy.
I normally recommend a fish oil supplement, but be sure to get one that is purified and tested to be free of mecury, pcbs, and other contaminants that could harm a developing baby. If you want the vegetarian version, you can get DHA made from algae.
The two products you might try are Ascenta NutraSea Original
and Deva Nutrition Vegan Omega-3 DHA