12 weeks: plum

As you move into the second trimester, baby shifts into the growth and maturation stage. After weeks in the critical development stage, almost all of baby's systems are fully formed.

By now, nearly all of your baby's organs, structures and systems are fully formed. The heart begins pumping several quarts of blood through your baby's body every day. Your baby has also begun to develop nerves and a spinal cord, allowing him to feel some types of pain. While your baby's brain is not the same size it will be at birth, it does have the same structure. Fingers and toes have separated and hair and nails continue to grow. Your baby is approximately 2.5 - 3.5 inches and weighs about 12 - 14 grams.

Also, the external genitals can now show definite signs of male and female gender. Before, where there was only reflex movement, your baby now moves spontaneously and at random, although his movements are still too slight to be felt. With the use of a Doppler, you may be able to hear your baby's heart beat at this office visit. It will sound very fast, similar to the sound of a running horse's hooves.