Get ready for a growth spurt. In the next few weeks, your baby will double his weight and add inches to his length. Right now he's about 4 1/2 inches long (head to rump) and 3 1/2 ounces. His legs are much more developed, his head is more erect than it has been, and his eyes have moved closer to the front of his head. His ears are close to their final position, too. He's even started growing toenails. And there's a lot happening inside as well. For example, his heart is now pumping about 25 quarts of blood each day, and this amount will continue to increase as your baby continues to develop.
Because your baby is moving well now, you may begin to feel his movements! Some women say that the early movements feel like gas bubbles or a slight flutter. If you have not yet felt the baby move, don't worry. Fetal movements are usually felt between the 16th and 20th week of pregnancy. You may feel your heart beating 'louder'. This is because there is a lot more blood in your body than normal. (about 50% more)