When you're pregnant it's important for you to eat plenty of healthy foods. Unfortunately, you may run into some compounds and bacteria that would not harm a healthy person, but they can cross the placenta and caus harm to your unborn baby. There are several foods that you should avoid during pregnancy because of the risk of contamination or because the foods themselves contain chemicals that might harm your baby.
There is some debate over whether or not pregnant women should avoid nuts during pregnancy. Because of the increasing prevalence of tree nut and peanut allergies in the United States, and because such allergies tend to run in families, many obstetricians have suggested that pregnant women avoid nuts during pregnancy if they have a family history of nut allergy. According to the March of Dimes, however, recent research suggests that avoiding nuts during pregnancy doesn't decrease the likelihood of the baby having a nut allergy. As such, current recommendations suggest avoiding nuts only if you have a nut allergy. It's worth noting that underlying or minor allergies may become more severe during pregnancy, so while you may be able to eat nuts normally, you might find yourself sensitive during pregnancy.
While seafood in general is part of a healthy diet, when you're pregnant you need to avoid certain types and preparations of fish. There are two reasons for this. First, explain Drs. Michael Roizen and Mehmet Oz in their book, "You: Having A Baby," many large predator fish, like shark and swordfish, accumulate large quantities of mercury in their bodies. Mercury is a neurotoxin, and can affect brain development in a fetus. As such, you should avoid these fish while pregnant. Tuna may also contain some mercury, but levels are generally lower, so eating tuna once a week during pregnancy is fine. When pregnant you should also avoid sushi because of the potential for bacterial contamination of raw fish.
Alcohol-Containing Foods and Drink
Alcoholic beverages are best avoided entirely during pregnancy, as they're associated with low birth weight, birth defects, and development of fetal alcohol syndrome. According to Heidi Murkoff and Sharon Mazel in their book "What To Expect When You're Expecting," alcohol in food should be avoided as well. Some foods, like rum cake, may have high levels of alcohol in them. Small amounts of alcohol that is cooked or baked into food -- such as wine in spaghetti -- does not pose a problem, since the alcohol cooks off.