When true labor begins, the mother may be aware of little more than a dull, generalized contraction, a sensation of weight or pressure in the lower body. Eventually, the contractions separate into a more specific sensation recurring every 20 minutes or so; if she places her hand on her midsection, she can feel a hardening followed by a release of the uterine muscle. With labor, the muscles of the uterus begin to contract. The lower part pulls sidewards and back on the ring of the cervix which is flattened out or “effaced,” losing its necklike character. At the same time, the contractions in the upper uterus are forcing the amniotic sac, containing fetus and fluid, downward against the cervical opening, dilating the cervix more with each push. From a diameter of little more than an inch at labor’s onset, the cervical opening enlarges to about 10 centimeters,or some four inches.
The contractions grow longer, and the intervals between them shorter. They should be timed precisely. When they reach a rythem of 10 minutes apart, it is fairly clear that labor has begun. Frequently, at this point in dilatation, or sometimes even earlier, a leak or flow of colorless liquid may come from the vagina. The “bag of water” enclosing the baby has ruptured, and the aminotic fluid escapes. The woman should not take a tub bath or have sex relations once this occurs, for there is risk of infecting the baby. For when this protective sac has been torn, the child’s head is at the opening of the cervix, and is exposed to the outside environment. Contractions frequently increase in intensity after the sac’s rupture, and labor proceeds more rapidly.
When the mother suspects that labor has begun, she should notify her physician. Generally the doctor will instruct her to go to the hospital when her contractions have reached a 10—to—5 minute pattern. She should take no food from this point on; her stomach should be empty in case there is an unexpected need for anesthesia, even when none is planned. On arrival at the hospital, the woman in labor is formally, but quickly, admitted, assigned a room, and taken there or to the labor floor directly. She is dressed in hospital gown.
An admission examination is then performed by her own doctor, a member of the resident staff, or a nurse, to determine the condition of fetus and mother, and the progress of the labor. The degree of dilatation is described in centimeters or inches, or in the special language of obstetricians and mid-wives “two, four, five fingers dilated.” Full dilation is 10 centimeters or five fingers breadth.
If labor is found to have begun in earnest, the mother’s genital area is washed and shaved (“prepped”) and in most cases she is given a warm soapy enema. The father-to-be is usually waiting elsewhere during the examination, but today most hospitals permit him to rejoin his wife after prepping, at least through early labor. Some hospitals will let the husband remain with her through out labor and delivery. With the complete effacement the cervix, and the full dilatation of its opening, the end of the first stage of labor has been reached. The duration of the first stage averages some nine hours for first births, and five hours for subsequent ones. Now the uterine contractions have grown long, lasting 50 to 100 seconds each, at intervals of 3 to 5 minutes. They are more intense. The second stage of labor has begun.