Fetal Development Stages of Growth: Month by Month
As the fertilized egg grows, a water-tight sac forms around it, gradually filling with fluid. This is called the amniotic sac, and it helps cushion the growing embryo.
The placenta also develops. The placenta is a round, flat organ that transfers nutrients from the mother to the baby.
In this month the basic structures of the fetus have begun to develop into separate areas that will form the head, chest, abdomen, and the organs that are contained within them.
A home pregnancy test should be positive at this stage of development.
At month 2, the fetus is about one-half an inch long (1.1cm). Facial features such as developing ears, eyelids, and nose tip are present. The limb buds are now clearly arms and legs, while the fingers and toes are still developing.
The neural tube (brain, spinal cord and other neural tissue of the central nervous system) is well 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.
At the end of this month the fetus has grown to 4 inches long and weighs about 1 ounce. The fetal heartbeat may be audible by Doppler ultrasound. The developing sex organs may be identified by ultrasound techniques.
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.
Your baby's reproductive organs also develop. By the end of the third month, your baby is fully formed.
The fingers and toes are well-defined. Eyelids, eyebrows, eyelashes, nails, and hair are formed. Teeth and bones become denser. Your baby can even suck his or her thumb, yawn, stretch, and make faces.
By the end of the fourth month, your baby is about 6 inches long and weighs about 4 ounces and resembles an infant; the eyes blink, the heartbeat is easier to locate.
The nervous system is starting to function. The reproductive organs and genitalia are now fully developed, and your doctor can see on ultrasound if you are having a boy or a girl.
You may begin to feel your baby move, since he or she is developing muscles and exercising them. This first movement is called quickening. You baby sleeps and wakes after regular intervals.
Hair begins to grow on baby's head. Your baby's shoulders, back, and temples are covered by a soft fine hair called lanugo.
The baby's skin is covered with a whitish coating called vernix caseosa. This "cheesy" substance is thought to protect baby's skin from the long exposure to the amniotic fluid. This coating is shed just before birth.
By the end of the fifth month, your baby is about 10 inches long and weighs from 1/2 to 1 pound.
Baby’s eyelids and eye lashes start fusing by the end of the month. Development of lungs takes place. Baby starts opening and closing of eyes. The brain grows rapidly in this month.
Your baby's skin is reddish in color, wrinkled, and veins are visible through the baby's translucent skin. Baby's finger and toe prints are visible. Baby responds to sounds by moving or increasing the pulse. You may notice jerking motions if baby hiccups.
By the end of the sixth month, your baby is about 12 inches long and weighs about 2 pounds.
Your baby will continue to mature and develop reserves of body fat. Your baby's hearing is fully developed. He or she changes position frequently and responds to stimuli, including sound, pain, and light. The amniotic fluid begins to diminish.
At the end of the seventh month, your baby is about 14 inches long and weighs from 2 to 4 pounds.
If born prematurely, your baby would be likely to survive after the seventh month.
Your baby will continue to mature and develop reserves of body fat. You may notice that your baby is kicking more. Baby's brain is developing rapidly at this time, and your baby can see and hear. Most internal systems are well developed, but the lungs may still be immature.
Your baby is about 18 inches long and weighs as much as 5 pounds. Baby’s face starts becoming chubby and the skin becomes smooth. To get prepared for delivery, most of the babies move their head down.
Your baby continues to grow and mature: the lungs are nearly fully developed. The baby’s body is extremely flexible easing the process of delivery. Antibodies flow through the placenta.
Your baby's reflexes are coordinated so he or she can blink, close the eyes, turn the head, grasp firmly, and respond to sounds, light, and touch. Baby is definitely ready to enter the world!
You may notice that your baby moves less due to tight space. Your baby's position changes to prepare itself for labor and delivery. The baby drops down in your pelvis. Usually, the baby's head is down toward the birth canal.