One drink isn't likely to hurt your baby, but no level of alcohol has been proved safe during pregnancy. The safest bet is to avoid alcohol entirely.

Consider the risks. Mothers who drink alcohol have a higher risk of miscarriage and stillbirth. Excessive alcohol consumption may result in fetal alcohol syndrome, which can cause facial deformities, heart problems, low birth weight and mental retardation. Even moderate drinking can impact your baby's brain development.

If you're concerned because you drank alcohol before you knew you were pregnant or you think you need help to stop drinking, talk with your health care provider.

Caffeine can cross the placenta and affect your baby's heart rate and breathing. Some studies suggest that drinking too much caffeine may be associated with a small decrease in birth weight or an increased risk of miscarriage and stillbirth. Other studies haven't reported the same risks.

Because of the unknowns, your health care provider may recommend avoiding caffeine during the first trimester and limiting the amount of caffeine you drink to less than 300 milligrams a day during the second and third trimesters.

Dairy products such as skim milk, mozzarella cheese and cottage cheese can be a healthy part of your diet. But anything containing unpasteurized milk is a no-no. These products may lead to food-borne illness.

Unless these soft cheeses are clearly labeled as being made with pasteurized milk, don't eat:

• Brie
• Feta
• Camembert
• Blue cheese
• Mexican-style cheeses, such as queso blanco, queso fresco, queso de hoja, queso de crema and queso asadero

During pregnancy, changes in your metabolism and circulation may increase the risk of bacterial food poisoning. Your reaction may be more severe than if you weren't pregnant. Rarely, your baby may get sick, too.

To prevent food-borne illness, fully cook all meats and poultry before eating. Look for the juices to run clear, but use a meat thermometer to make sure. Skip medium or rare burgers and sausages. Be careful with hot dogs and deli meats, too. These are sources of a rare but potentially serious food-borne illness known as listeriosis. Cook hot dogs and heat deli meats until they're steaming hot — or avoid them completely.

Fish and other Seafood can be a great source of protein and iron, and the omega-3 fatty acids in many fish can help promote your baby's brain development. In fact, a British study suggests that skimping on seafood during pregnancy may contribute to poor verbal skills, behavioral problems and other developmental issues during childhood. However, some fish and shellfish contain potentially dangerous levels of mercury. Too much mercury may damage your baby's developing nervous system.

The bigger and older the fish, the more mercury it may contain. The Food and Drug Administration (FDA) encourages pregnant women to avoid:

• Swordfish
• Shark
• King mackerel
• Tilefish

So what's safe? Some types of seafood contain little mercury. Although concerns have been raised about the level of mercury in any type of canned tuna, the FDA says you can safely eat up to 12 ounces a week (two average meals) of:

• Shrimp
• Canned light tuna (limit albacore tuna and tuna steak to no more than 6 ounces a week)
• Salmon
• Pollock
• Catfish

To avoid ingesting harmful bacteria or viruses, avoid raw fish and shellfish — especially oysters and clams — and anything caught in polluted water. Refrigerated smoked seafood is also off-limits, unless it's an ingredient in a casserole or other cooked dish.

Most fish should be cooked to an internal temperature of 145 F. The fish is done when it separates into flakes and appears opaque throughout. Cook shrimp, lobster and scallops until they're milky white. Cook clams, mussels and oysters until their shells open. Discard any that don't open.

Although herbal tea may be soothing, avoid it unless your health care provider says it's OK — even the types of herbal tea marketed specifically to pregnant women. There's little data on the effects of specific herbs on developing babies. And large amounts of some herbal teas, such as red raspberry leaf, may cause contractions.

Vitamin A: You should avoid taking supplements containing vitamin A. Fish liver oil also contains high levels of vitamin A. Having too much vitamin A may harm your unborn baby.

Serious allergies to nuts and nut products and some seeds affect about 1 to 2% of people. Your baby may be at higher risk of developing a nut allergy if you, the baby's father, brothers or sisters have certain allergic conditions such as hayfever, asthma and/or eczema. If your baby is in this higher-risk group, you may wish to avoid eating peanuts and peanut products when you're pregnant and breastfeeding.