Development of the FetusDuring the second trimester, the fetus will grow from approximately two to four inches to thirteen to sixteen inches. He, or she, will also gain a significant amount of weight going from half an ounce to weighing in at two to three pounds as fat begins to develop on the fetus. During this time the placenta is fully developed.
The fetus will go through cycles of sleep and wakefulness. The baby will move, kick, wiggle and squirm and mother will begin to feel the movement for the first time. Called quickening, many mothers refer to this movement as a fluttering feeling. At this time the fetus can hear the mother’s voice and may even respond to certain stimuli. He or she will also be developing their sucking and swallowing reflexes, possibly sucking on fingers and swallowing amniotic fluid.
The eyes will gradually move to the front of the face and the ears have moved to the sides of the head. A white substance called vernix caseosa appears on the fetus to protect its thin skin and soft hair, called lanugo, grows. The vernix caseosa is absorbed by the skin, some of it may still be on the baby at birth. Fingers and toes will become fully separated and the baby’s eyes are beginning to open.