Your baby's arms, hands, fingers, feet and toes are fully formed.  Your baby can open and close its fists and mouth.  Fingernails and toenails are beginning to develop and the external ears are formed.  The beginnings of teeth are forming.  Your baby's reproductive organs also develop, but the baby's gender is difficult to distinguish on ultrasound.  By the end of the third month, your baby is fully formed.  All the organs and extremities are present and will continue to mature in order to become functional.  The circulatory and urinary systems are working and the liver produces bile.  At the end of the third month, your baby is about 4 inches long and weighs about 1 ounce.  Since your baby's most critical development has taken place, your chance of miscarriage drops considerably after three months.