The American Pregnancy Association offers these recommendations:

• Make sure you get at least 400 micrograms of folate or folic acid each day, either from your diet or from a supplement.
• Get at least 1,000 milligrams per day of calcium -- the equivalent of three 8-ounce glasses of skim milk.
• Talk to your doctor about taking a special vitamin for women who are pregnant or are likely to become pregnant.
• Reduce -- to no more than 300 milligrams daily -- your intake of caffeine, which can affect fertility and the body's ability to absorb calcium and iron.
• Avoid alcohol, drugs, cigarettes and artificial sweeteners.