We all know that smoking, drinking and doing illicit drugs are major no-nos when you're pregnant. But what other hazards are out there that pregnant women should be wary of?

Seafood

While fish are a great source of protein and heart-healthy omega-3 fatty acids, some are also chock full of mercury, a metal that can harm the developing brain of a fetus. Swordfish, tilefish, king mackerel and shark are particularly high in mercury and should be avoided during pregnancy, according to the U.S. Department of Health and Human Services. Pass on sashimi and other uncooked seafood, including raw oysters, too, health officials say. In addition to putting you and your baby at risk of mercury exposure, they may contain parasites such as tapeworm, which can rob your baby of vital nutrients.

Dr. Joel Evans doesn't believe pregnant women should be passive, compliant patients, who simply listen to everything their health care providers tell them to do for nine months. He believes women—and their partners—should be active participants in the whole pregnancy, from conception to prenatal care to childbirth to postpartum care. That's why he wrote The Whole Pregnancy Handbook: An Obstetrician's Guide to Integrating Conventional and Alternative Medicine Before, During and After Pregnancy with Robin Aronson.

When Dr. Andrea Pennington got pregnant, she wanted to keep exercising at the pace she was used to. To make sure she’s not over-doing it, she’ll meet with instructor Faith Hunter to learn some safe and helpful yoga poses for women in their first trimester.