Your baby's facial features continue to develop.  Each ear begins as a little fold of skin at the side of the head.  Tiny buds that eventually grow into arms and legs are forming.  Fingers, toes and eyes are also forming.  The neural tube (brain, spinal cord and other neural tissue of the central nervous system) is swell formed.  The digestive tract and sensory organs begin to develop.  Bone starts to replace cartilage.  The head is large in proportion to the rest of the baby's body.  By the end of the second month, your baby is about 1 inch long and weighs about 1/20 of an ounce.  At about 6 weeks, your baby's heart beat can usually be detected.