Week 6

Your Baby's Development
By week 6, the neural tube along your baby's back has closed over. In addition, there has been major growth in the brain as it grows in size to fill the now-formed, enlarging head. Optic vesicles, which later form the eyes, begin to develop this week on the side of the head, as do the passageways that will comprise the inner ear.

Even though it can't yet be heard, your baby's heart will begin to beat around this time. And the beginnings of the digestive and respiratory systems are forming, too. Small buds that will grow into your baby's arms and legs also appear this week. These developments are taking place on an extremely small scale, though - your baby only measures 0.08 to 0.16 inches (2 to 4 millimeters) from crown to rump!

Your Body
Common pregnancy complaints may hit in full force this week. You may feel extreme fatigue, even before you know you're pregnant, as your body adjusts to the demands of pregnancy. In addition, tender, aching breasts and nausea and vomiting, or morning sickness, may leave you feeling less than great. Despite its name, morning sickness can occur at any hour or all day, so don't be surprised if your upset stomach doesn't pass by noon. Nausea isn't the only thing that has you running to the toilet, though - the pregnancy hormone, hCG, causes you to urinate more frequently, too.