If we could look into the womb just before the time of labor we would find the fœtus attached by the cord to the placenta and floating in a sac of water. This sac is formed partly of the placenta and partly of the membrane; the side of the placenta opposite to the child being attached to the womb. Just before labor the child takes a position with its head downward, its lower limbs flexed and its arms folded upon its breast. This allows it to come in the usual way, head first. But sometimes, for various reasons, it does not take this position and some part other than the head, for instance, the feet, may be born first.
Labor pains are caused by the contraction of the muscles of the womb in an effort to expel the fœtus. The muscles, contracting, push the fœtus downward to the mouth of the womb but push ahead of it a portion of the membrane enclosing some of the water. This is called the "bag of waters." As it presses against the mouth of the womb it causes it to dilate so as to allow the fœtus to pass through into the vagina. The fœtus, preceded by the bag of waters, then descends through the vagina or birth canal until it comes to the external opening of the vagina. This it must dilate before it can pass through it. The bag of waters should rupture normally while it is being pushed through the external opening. Sometimes the bag does not rupture directly in front of the descending head but further up along the side. Then a portion of the membrane may be over the face of the child when it is born. This is what is called being "born with a veil" or "born with a caul."
The bag of waters helps dilate the parts much easier than the fœtus could do it alone. When the bag breaks the water lubricates the parts so as to make the passage of the child easier. When it breaks, as it sometimes does, at the beginning of labor we have what is termed a "dry labor." This usually is much slower than it would be otherwise. The majority of the cases of labor extend over a period of from twelve to twenty-four hours.
Sometimes the external opening of the vagina does not dilate enough to allow the passage of the child. As the head presses hard against the perineum it tears it. This tear should be repaired immediately after completion of labor.
When the baby is born it is fully formed but its lungs have never contained air. At the first cry the air rushes into the lungs and expands them. At birth there is a change in the circulation of the blood of the baby. Before this time, the blood has passed to and from the placenta through the cord but now this is stopped. Before birth there was an opening between the right and left sides of the heart but this closes during the first few days of the child's life. To assist in this closure, it is wise to keep the child on its right side for a few days. Rarely, this opening never closes and we have what is called a "blue baby," which seldom lives very long.
In a great many cases, painless childbirth could be a possibility by a little attention to diet, exercise and other hygienic measures during the last few months of pregnancy. Knowing this, it seems inconceivable that any woman would neglect to so fully inform herself on these matters that both she and her child could have all benefit of the investigations of science.