Taking fish oil supplements while pregnant may boost your baby's smarts. Researchers found that 2 1/2 -year-olds whose mothers supplemented with fish oil daily during the last half of pregnancy scored better in language comprehension, vocabulary and eye-hand coordination than those whose moms didn't. For neurological and visual development, a fetus needs long-chain fatty acids from the mother's diet. While these are readily available in seafood, experts recommend that women limit prenatal fish consumption to 12 ounces weekly to avoid contamination by mercury. The supplements contained the benefits of one fish serving daily, but without risk of mercury exposure from eating the fish itself. Check labels to be sure supplements have been tested for mercury, or visit consumerlabs.com for reputable manufacturers.