Pop Your Prenatal Vitamin Daily

Taking it will help ensure that you get the balance of nutrients your baby needs, like folic acid and vitamin B12 to make red blood cells, vitamin C to produce collagen, vitamin D for bone building, and zinc for brain development. If your vitamin upsets your stomach, don't just ditch it: Try taking it with a meal, or talk to your doctor about switching brands.

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Get Omega-3s

Fish, rich in omega-3 fatty acids, may boost your baby's brainpower. In a study from Harvard Medical School, the more fish women ate during the second trimester, the higher their babies scored on a mental-development test at 6 months of age. Omega-3s are found in brain-cell membranes, so there are plenty of ways they can influence brain function, says Lisa Eliot, PhD, assistant professor at Rosalind Franklin University of Medicine and Science, in Chicago. If you don't like fish, talk to your doctor about taking a fish-oil supplement.

Be Mindful of Mercury

Fish is good for your baby's brain, but you do need to take a few precautions. Mercury contamination in some fish may be harmful. The Food and Drug Administration advises all pregnant women to avoid shark, tilefish, king mackerel, and swordfish completely, since they contain the highest levels. Some lower-mercury options: salmon, catfish, pollack, whitefish, tilapia, and shrimp. Even with these varieties, you should limit all fish to 12 ounces (about two meals) per week. And opt for canned light tuna over canned white albacore, which has more mercury.

Munch on Fruits and Veggies

Produce contains antioxidants, which are good for your baby. "Antioxidants protect the baby's brain tissue from damage," says nutritionist Elizabeth Somer, RD, author of Nutrition for a Healthy Pregnancy. Choose deep-colored produce -- like dark leafy greens, papaya, blueberries, and tomatoes -- for the biggest antioxidant punch. Just remember to wash all fruits and vegetables thoroughly, even fruits that have a rind (since cutting it will drag germs through the flesh).