Guide to Being 21 Weeks Pregnant

What's Going On in Your Body

This week, your care provider starts measuring your baby from crown to heel instead of crown to rump. He or she should be about 10 or so inches long and weigh around 12 ounces. The top of your uterus is now about half an inch above your belly button.

Your baby is still growing quickly, but the growth rate is beginning to slow. The digestive tract is maturing, helped along by the gulps of amniotic fluid the baby's been taking. Your placenta still provides most of the baby's nutrition, but it's getting some caloric intake through its own actions, which is really amazing! He or she can also taste the fluid with the brand-new taste buds developing on the tongue. Teeth buds are starting to form in the gums, too.

Until this point in the pregnancy, your baby's spleen and liver have done most of the work to produce blood cells, but around now, the bone marrow starts to take over. The spleen will stop its blood-making duties in week 30 or so, but the liver continues until later in the third trimester.

But enough about you and your baby; on the next page, we'll talk about the tasks your partner can do this week.