From Fertilization to the Birth of the Baby

Let's go back for a moment to the instant of fertilization.

As soon as the egg is fertilized, it begins to divide and grow as it is moved on down the fallopian tube. As you know, it enters the uterus, and after a while implants itself in the uterine wall. The whole process takes several days. The uterus, as you have read is ready to nourish the egg as it grows.

Later, with increase in size, the growing baby becomes surrounded by two strong coverings and suchioned in fluid. Which protects it from jolts and shocks. The time between conception and birth of the baby is called the period of gestation. The baby grows inside the womb of its mother. This is the period during which the mother is said to be pregnant. In human beings, pregnancy, or gestation, averages 266 days, or about eight-and-a-half months, from the moment of fertilization, and 280 days, or nine months, from the beginning of the last menstrual period.

The baby, first called an embryo, later a foetus, grows by cell division, from one cell at conception to over 200 billion cells at the time of birth. It is nourished by the mother by means of a thick, disc-shaped collection of blood vessels called the placenta. This is connected with growing embryo by means of a long, ropelike cord, the umbilical cord. Through the blood vessels in this cord the embryo receives food and oxygen and disposes of waste products like carbon dioxide, but the mother's blood does not enter the embryo. The embryo manufacures its own blood. The human embryo at first resembles embryos of other animals. For a short time it has the beginning of gills, as in fish embryos, although they are not really gills; later it appears to have a tail; stilla later its body is covered with fine, downy hair.

At four weeks the embryo is about 1/4 inch long (as long as this :- but somewhat curled). It no longer has gill-like ridges, but still has a tail; and it would be difficult to tell it apart from the ambryo of a fish, turtle, chicken, or any other animal. At eight weeks the embryo is about 1 inch long, and it would take about five hundred such embryos to weigh a pound. Even though it is this small, it already has a large-looking head with the beginnings of eyes, ears, a nose, and a mouth. Its heart is now pumping blood through its small body.

At twelve weeks the embryo has made a great spurt of growth and is now about 4 inches long, although it weighs only about 1/3 ounce - about fifty embroys to a pound. At sixteen weeks it has grown to be 6 inches long and weighs 1/3 pound. Its bones have begun to develop, and its arms and legs can move. The mother may now be able to feel the first faint flutter of activity inside her, called quickening. When she feels this she knows with a new certainty that a live being is inside her. By this time the being is called a foetus, no longer an embryo.

At twenty-one weeks the foetus would be about 10 inches long if its legs were stretched out straight, and it weighs about 3/4 pound. Its body is now covered with downy hair. At twenty-five weeks the foetus is about a foot long and weighs perhaps 1 1/4 pounds. It is beginning to lose the hair that covered its body and looks quite a lot like a baby now, except that it is thin and has not yet begun to store up fat. At about twenty-nine weeks - seven months - is is 14 inches long and probably weighs over 2 pounds.

The body hair has all gone. (By twenty-four to twenty-eight weeks the baby has matured enough so that if it were to be born ahead of time it would have a bare chance to live, if well cared for in an incubator, a little, heated, enclosed, box-like bed which keeps a baby warm and protected. Such a baby is called premature, as is any baby born weighing less than 5 1/2 pounds) During months eight and nine the foetus grows rapidly to an average weight of 7 or 8 pounds. At the end of the nine-month gestation period, it is ready to be born, all 200 billion cells of it.