Vary your diet if you're a vegetarian.
"Vegetarians who follow a diet that includes milk and egg products should have no trouble obtaining the necessary nutrients in pregnancy," says Swinney. Just be sure to eat an assortment of grains, fortified cereals, legumes, vegetables, and seeds throughout the day.
Vegans, who eat no animal products, may need vitamin B12, vitamin D, zinc, and calcium supplements prescribed by their doctors. Also, the iron found in plant foods may not be absorbed as well as the iron in meats, warranting a supplement.
If you're a religious Muslim who doesn't eat pork or a religious Jew who doesn't eat pork or shellfish or combine meat and dairy products at the same meal, don't worry. "As long as a diet has a variety of foods from different food groups," says Swinney, "you should get the nutrients you and your baby need." One caution: Some religions have fasting days, but pregnant women should never fast.
If you are lactose intolerant, opt for calcium-rich nondairy foods such as collard greens, figs, and sardines with bones; your doctor may also recommend calcium supplements. Nonprescription drops and tablets containing lactase, the intestinal enzyme that's responsible for lactose digestion, are safe to take with dairy foods during pregnancy, says Ward.