Planning ahead. Most birth defects occur three to six weeks after conception. To be safe, begin taking a daily prenatal vitamin that contains at least 400 micrograms of folic acid and not more than 5,000 units of vitamin A two months before going off birth control. Avoid herbal formulations. (See motherisk.org.) And make sure you’re immune to German measles and chickenpox, which can cause birth defects.
Weight gain. Don’t eat for two. In a 2002 report, the Institute of Medicine recommended that women not increase their food intake in the first trimester. Overweight women should gain no more than 15 to 25 pounds; average women, 25 to 35 pounds; thin women, 28 to 40 pounds.
Food. Spend calories wisely. High levels of mercury in shark, swordfish, king mackerel and tilefish may harm the developing brain, so the FDA recommends that pregnant women avoid them. In March the FDA advised that pregnant women limit their intake of albacore tuna (the kind found in most cans) to no more than six ounces a week. (See Physicians for Social Responsibility’s new guide to healthy fish at mercury action.org/fish.) Also avoid soft, unpasteurized cheeses (such as blue-veined ones), deli meats and uncooked hot dogs that can carry the listeria bacteria, which cross the placenta. And be wary of uncooked seafood, which can carry hepatitis A. Peanuts are a good source of folate and protein, but pregnant women with a family history of allergies may want to avoid them. (See foodallergy.org.)
Drink. Until researchers establish a safe level of alcohol consumption for pregnant women, moms-to-be should avoid it. Women should also switch to decaffeinated coffee or limit intake to one or two cups a day. Diet sodas containing Nutrasweet appear to be safe.
Meds. “If you can avoid using drugs in pregnancy, avoid them,” says Massachusetts General Hospital’s Laura Riley, chair of the committee on obstetric practice for the American College of Obstetricians and Gynecologists. Check with your doctor before taking aspirin and ibuprofen; acetaminophen appears to be safe.
Lifestyle. The current issue of Obstetrics & Gynecology reports that casual airline travel poses little risk of radiation exposure. And, contrary to conventional wisdom, it’s OK to dye your hair and polish your nails. “There’s not really any data to suggest it’s harmful,” says Riley. But don’t smoke, and avoid hot tubs and saunas, which can increase the risk of miscarriage. Ordinary tubs and showers are fine.
Chill. Some 97 percent of babies in the United States are born healthy. So don’t worry. But as any pregnant woman knows, that’s easier said than done.
