Fetal Development

Beginnings

Conception takes place and pregnancy begins when the male reproductive cell sperm unites with the female reproductive cell ovum. This union usually occurs in a fallopian tube. The fertilized egg, a single cell, holds the complex genetic blueprint for every detail of the developing child -- including hair and eye color, height, sex, and skin tone. This new life inherits 23 chromosomes from each parent. The fertilized egg travels into the uterus where the lining is prepared for implantation. It becomes attached to the internal uterine wall. At the point of attachment, the placenta forms. The placenta is composed mostly of blood vessels from the mother and baby. There is no direct mixing of blood between the mother and child. Through the thin walls of the placenta's blood vessels, oxygen and nutrients pass from the mother to her baby, and waste products from the child's blood pass into the mother's blood to be excreted. Growth proceeds at an enormous rate. Cells quickly differentiate into various tissues and organs.

First Trimester

A baby's heart begins beating 18-25 days after conception. By the end of the first month, arms, legs, eyes, and ears have begun to show. Muscles and backbone as well as the brain, spinal cord, and nervous system are forming. At one month old, the embryo is 10,000 times larger than the original fertilized egg. Brain waves can be recorded and all major organs are formed, but not completely developed by 6 1/2 weeks. By the 35th day, five fingers can be distinguished in the hand.   By the end of the second month, the child is about 1 1/4" long. He or she is now called a fetus -- a Latin term for "young one". The stomach produces digestive juices and the kidneys begin to function. Everything that is found in a fully developed adult is now present. Forty sets of muscles operate. Distinct arms and legs have formed. Cartilage is being replaced with bone. The baby is 2 1/2 - 3" long by the end of the third month. Urination occurs. A baby's facial profile is evident. The baby alternates between sleeping and being awake, makes vigorous movements, opens and closes its mouth, sucks, swallows, and curves its fingers around an object placed in its hand. Fingerprints are established. Amniotic fluid is inhaled and helps to develop the respiratory system.

Second Trimester

At four months, the child measures more than six inches long. The fingers and toes have soft nails. Ears are functioning and the baby hears quite a bit. The child can kick, turn somersaults, twist and jump. Eyebrows begin to appear and hair is growing on the infant's head.   Mother's feel the baby move during the fifth month. The child is 8-10 inches long and weighs about one pound. Soft hair and a protective coat of vernix cover the baby. The child sucks its thumb. The baby may jump in reaction to a loud noise.   The child's face is fully formed and its eyes can open during the sixth month. The skin is shiny and thin with little or no fat deposits under it. Sweat and oil glands function. The baby is nearly two pounds and thirteen inches long. With the proper intensive care, the child may survive if born in this month.

Third Trimester

The baby recognizes its mother's voice and uses the senses of vision, taste, hearing and touch during the seventh month. It can cry and discern sweet and sour flavors. Hiccups are common. Fat deposits form under the skin for nourishment and insulation and the child fills out to three pounds. There is a good chance of survival if the baby is born this month. By the end of the eighth month, the child weighs five pounds and is nearly eighteen inches long. The lungs may still be immature, but most systems are well developed. The skin begins to thicken. Antibodies are building up within the child's system and there is extensive brain growth during this time. Baby's lungs are able to breathe on his or her own by the ninth month. The child gains about 1/2 pouond a week. The baby may seem less active since it is very confined without much extra space in the uterus. Final preparations make the baby ready for birth. The heart is pumping 300 gallons of blood each day. The child is ready to be born. Welcome, little one, to our world!

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