Your Baby's Development

Until now, the embryo has been a mass of cells. But now a distinct shape begins to form. The neural tube (which will become the spinal cord and brain) runs from the top to the bottom of the embryo. A bulge in the center of the embryo will develop into your baby's heart.

At this time, the placenta develops. It's through the placenta and its fingerlike projections, called chorionic villi, that an embryo gets nourishment from its mother.

Your Body

Even if nausea hasn't hit you yet, you'll want to steer clear of some foods. Foodborne illnesses, such as listeriosis and toxoplasmosis, may cause birth defects or even miscarriage.

Here are some foods to avoid:

• soft, unpasteurized cheeses (often advertised as "fresh") such as feta, goat, Brie, Camembert, and blue cheese
• unpasteurized milk, juices, and apple cider
• raw eggs or foods containing raw eggs, including mousse and tiramisu
• raw or undercooked meats, fish, or shellfish
• processed meats such as hot dogs and deli meats (if you eat them, they should be well-cooked)
• fish high in mercury, including shark, swordfish, king mackeral, or tilefish

Toxoplasmosis also can spread from soiled cat litter boxes, so try to have someone else clean the litter box during your pregnancy.