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Month 1
As the fertilized egg grows, a water-tight sac forms around it. This is called the amniotic sac, and it helps cushion the growing embryo. The placenta also develops. This transfers nutrients from the mother to the baby. The baby is about 1/4 inch long. -
Month 2
The baby's facial features continue to develop. The neural tube is formed as well. The arms and legs start to form as well as the fingers, toes, and eyes. The baby is about 1 inch long and weighs about 1/30 of an ounce. -
Month 3
The baby's hands, arms, legs, feet, and toes are fully formed. The fingernails and toenails are starting to develop. The beginnings of the teeth are also forming. By the end of the third month, the baby is fully formed. The baby is about 4 inches long and weighs about 1 ounce. -
Month 4
The baby's heartbeat is now audible. The eyelids, eyelashes, eyebrows, nails, and hair are formed. Teeth and bones become denser. The baby's nervous system is starting to function. During month 4, you can see the gender of the baby. The baby is about 6 inches long and weighs about 4 ounces. -
Month 5
The baby may start moving during this period. The shoulders, back, and temples are covered by a soft hair called lanugo. The baby's skin id covered with a white coating called vernix caseosa. This is to protect the baby's skin from the exposure to the amniotic fluid. This will shed off just before birth. The baby is about 10 inches long and weighs from 1/2 to 1 pound. -
Month 6
The baby's skin is now red and wrinkled and veins are visible through the baby's skin. Toe and finger prints are now visible also. The baby responds to sounds by moving or increasing the pulse. The baby will jerk around if he/she hiccups. The baby is about 12 inches long and weighs about 2 pounds. -
Month 7
The baby's hearing is fully developed. He/she changes position frequently and responds to stimuli, including sound, pain, and light. The amniotic fluid begins to decrease. The baby is about 14 inches long and weighs from 2 to 4 pounds. -
Month 8
The baby may begin kicking more and more. The brain is developing rapidly and the baby can see and hear. Most internal systems are well developed but the lungs may still be immature. The baby is about 18 inches long and weighs as much as 5 pounds. -
Month 9
The baby's are nearly fully developed. The baby can blink, turn its head, close eyes, grasp firmly, and respond to sounds, light, and touch. The baby may move less and less due to tight space. The baby's position changes to prepare for labor and delivery. The baby is about 18 to 20 inches long and weighs about 7 pounds.