16 Weeks

Our Babies at 16 weeks

How your baby's growing: At 4 1/2 inches long (head to bottom) and 3 1/2 ounces, your baby is about the size of an avocado. In the next three weeks, she'll go through a tremendous growth spurt, though, doubling her weight and adding inches to her length. Her lower limbs are much more developed now. Her head is more erect than it has been, and her eyes have moved toward the front of her head. Your baby's ears are close to their final position, too.

Some of her more advanced body systems are working, including her circulatory system and urinary tract. Her heart is now pumping about 25 quarts of blood each day, circulating her total blood volume through her body many times. (By the end of your pregnancy, this will increase to about 190 quarts.) The patterning of her scalp has begun, though her hair isn't recognizable yet. Although closed, her eyes are moving (slowly), and she's even started growing toenails.