What you eat during your pregnancy has a direct effect on the growth and development of your baby. It is important to eat a well-balanced diet that includes lean meats or meat alternatives, whole grains, low-fat dairy products, and plenty of fruits and vegetables. In addition to increasing your consumption of healthy foods, there are certain foods you need to limit or avoid. Some foods contain substances that can affect your baby’s development, while others put you at risk of developing an infection that can be passed to your baby.

Mercury is naturally found in the environment and is also released by industrial pollution. When mercury settles into water, it is converted into methylmercury, a more dangerous form. Methylmercury can accumulate in the fatty tissue of fish. Most fish contain trace amounts of methylmercury, which is unlikely to cause harm. But, large, predatory fish can contain high levels of methylmercury.

The United States Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) provide these recommendations for women who may become pregnant, are pregnant, or are nursing:

• Avoid eating fish that contain high levels of mercury, including swordfish, shark, king mackerel, and tilefish.
• Eat up to 12 ounces (340 grams) of fish containing low levels of mercury per week. Fish containing low levels of mercury include shrimp, canned light tuna, salmon, pollock, and catfish. Because white tuna and tuna steak contain higher levels of mercury, women are advised to eat no more than six ounces of these fish per week.
• If you usually eat locally caught fish, check advisories about the safety of the fish. If there are no advisories, limit your intake to 6 ounces (170 grams) per week.

Pregnant women should also avoid raw and undercooked fish, especially shellfish (eg, oysters, clams) because they can contain disease-causing organisms. Cook fish until it is opaque and flakes easily with a fork.

Unpasteurized soft cheeses and ready-to-eat meats should be avoided during pregnancy because they may contain bacteria that causes listeriosis, a form of food poisoning that is especially harmful to unborn babies. Listeriosis is associated with miscarriage, premature delivery or stillbirth, and serious illnesses in newborn babies.

To avoid listeriosis, the FDA advises pregnant women to do the following:

• Avoid eating hot dogs or luncheon meats that have not been reheated until steaming hot.
• Do not eat soft cheeses (eg, feta, brie, Camembert, Roquefort, Mexican soft cheeses) unless they are made with pasteurized milk.
• Avoid refrigerated pâtés or meat spreads.
• Avoid refrigerated smoked seafood unless it has been cooked.
• Do not consume unpasteurized milk or foods made from it (eg, eggnog, Hollandaise sauce).

Undercooked meat, including poultry and eggs, should be avoided during pregnancy. These foods can increase your risk of a number of foodborne illnesses, including listeriosis, E. coli, Campylobacter infections, salmonellosis, and toxoplasmosis.

To ensure your meat is well-cooked, use a meat thermometer. Follow these temperature guidelines when cooking food:

Pregnant women should also avoid eating raw vegetable sprouts (eg, alfalfa, clover, radish) and unpasteurized fruit or vegetable juices. These can carry disease-causing bacteria.

In addition, pregnant women should limit their consumption of liver, since it contains high levels of vitamin A, which could potentially cause harm to a developing baby.

When preparing and handling foods, the March of Dimes recommends you take the following precautions to avoid foodborne illnesses:

• Before and after handling food, wash your hands with soap and hot water.
• Wash any item or area that comes in contract with raw meat, poultry, or fish.
• Separate ready-to-eat food from raw meat, poultry, or fish.
• Before eating raw fruits and veggies, rinse them and use a scrub brush to remove dirt.
• Take the outermost leaves off of lettuce and cabbage.
• Refrigerate leftovers right away. Also, avoid eating cooked food that has been out of the refrigerator for more than two hours.
• Keep your refrigerator temperature below 40ºF (4ºC) and your freezer at 0ºF (-18ºC) or below. Buy a thermometer to check the temperature.