Pregnant women may be eating for two, but there a few foods they need to avoid.

Most people know that smoking and drinking and alcohol are no-no's during pregnancy, but what about foods and beverages that are normally healthy? There are some things that are good for people's nutrition in general, but still need to be avoided while a woman is pregnant.

Let's start with coffee and tea. Many people drink these beverages every morning, but an expecting woman may need to rethink her daily dose of energy. Caffeine has been shown to have an effect on the developing baby's heart rate. There is some evidence that caffeine might increase the risk of miscarriage. Many doctors will advise their patients to stick with a maximum of 200 milligrams of caffeine per day, equal to about two cups of coffee or four cups of tea. Women who have high-risk pregnancies or have had trouble conceiving may want to reduce that further or forgo caffeinated beverages completely.

When it comes to food, most healthy and nutritious choices are fine. Anything that's not good for you any of the time should also be avoided while a woman is pregnant. This is especially true for high saturated fat and high added sugar content because expecting mothers are at risk of developing gestational diabetes or high blood pressure that could lead to pre-eclampsia.

There are some foods that must be avoided during pregnancy even though they are perfectly healthy otherwise. It's especially important to wash all raw fruits and vegetables and avoid consuming raw sprouts. The sprouts' forms have so much surface area that they cannot be washed enough to be considered safe. Mothers-to-be should also avoid deli meats, raw or undercooked fish and meat, and unpasteurized cheeses, which may carry the risk for listeria. Listeria is uncommon, but it is very likely fatal to an unborn child, so it is not considered worth it to take any risk.

READ MORE: 15 Ways Women Can Avoid Nutritional Deficiencies While Pregnant

Fish is a healthy food with many compounds that are beneficial to a growing fetus, but unfortunately, the fish in our world has been polluted by mercury. Mercury is a toxin and while an adult might not be affected by small amounts of it, an unborn child will be. Pregnant women should limit themselves to twelve ounces of small fish such as salmon, chunk lite tuna, or shrimp, who don't carry as much of the toxin as larger fish who live longer and consume smaller fish. Fish to avoid include all large fish, such as swordfish, king mackerel, tuna, and shark.

Most pregnancy nutrition is common sense. Eat healthy foods and listen to one's body. But there are some substances that can affect such a tiny being different than a grown adult, so it's important to do your research.

NEXT: Healthy Substitutes For Fast Food Pregnancy Cravings