Want your baby to be a genius? How about great at sports? Several studies show that higher levels of fish oil intake will help. As a bonus, the babies also had better visual acuity.
DHA, which is predominantly found in fish oil, is the main oil that makes up our brain. When low, it is associated with depression.
As the baby takes the DHA from the Mom's brain if there is not enough in the diet, this is one of the two main causes of postpartum depression (the other is low progesterone).
In the first study involving 109 infants and their mothers, higher cord blood levels of DHA (docosahexaenoic acid from fish oil) was found to be associated with more optimal visual, cognitive, and motor development in infants during the first year after birth. The authors concluded that there is a "..need for substantial increases in this critically important fatty acid during the third trimester spurt of synaptogenesis (brain connection formation) in brain and photoreceptor development."
The second study, which was placebo-controlled, looked at visual acuity and found that even low dose fish oil supplementation during pregnancy resulted in the babies having better vision.
The third study also showed higher fish intake was associated with smarter babies, but in this study a bit of the effect was cancelled out if the hair mercury levels were high. This is why even though nutrition from food is usually the best source, during pregnancy it may be best to get the fish oil instead of the fish. In addition to making a smarter baby, the fish oil (at 4 gm a day) was shown to be safe in pregnancy.
Just be sure the fish oil is mercury free, toxin free and stable (not rancid). Don't eat fish oil if you would not eat a piece of fish that tastes like the oil, because it means the oil is rancid.