Labor is commonly divided into three stages that typically overlap each other.

First Stage

During the first stage (about 13 hours for a woman having her first child) uterine contractions begin. An increase of enzyme levels chews up the collagen that holds together the fetal membrane. This causes the amniotic sac to rupture (when a woman's "water breaks.") The contractions are usually spaced from 10 to 20 minutes apart. Initially the contractions are gentle, but they tend to become more powerful and can be uncomfortable.

When should the mother go to the hospital?
Some mothers prefer not to use hospital facilities and instead give birth at home, usually with a midwife or physician present to help with the delivery However, from 10 to 15 percent of deliveries do require special help. For this reason, unless complete facilities can be made available in the home, doctors usually recommend that mothers be in the hospital or other birthing facility within a few hours after the beginning of labor.

Second Stage

The second stage of labor usually lasts about 90 minutes. During this stage, the cervix opens and the baby begins to move down the birth canal. At this point the mother may use her abdominal muscles to help push the baby along. This second stage of labor may often be shortened considerably by having the mother give birth in a vertical position, for example, by using a bed or room especially designed to include a birthing bar. When the mother is upright, gravity helps the baby move down the birth canal. Using the upright position can reduce labor to about 30 minutes. At the end of the second stage of labor, the baby is born.

Birth
During birth, the human fetus is forced through the birth canal under extreme pressure and is intermittently deprived of oxygen. During this time, the baby secretes the hormones adrenaline and noradrenaline, collectively classified as catecholamines, at levels that are higher than they are likely to be at any other time throughout his or her life. Adrenaline helps open up the lungs, dry out the bronchi, and thus achieve the switch from a liquid to an air environment. Noradrenaline slows the heartbeat, enabling the fetus to withstand fairly lengthy oxygen deprivation. Babies delivered by Cesarean often have respiratory problems. One reason for such problems might be that the infant has not benefited from the usual stress of birth!

Are all babies born in the head-first position?
About 97 percent of babies are born in the head-first position. The fetus's skull is soft and pliable, which helps the head to pass through the birth canal. However, 2.4 percent of babies are born rump first (breech birth). During a breech birth, great care must be taken to avoid damage to the baby's head. An even rarer occurrence is the shoulder presentation. This occurs in only one birth out of 200. The shoulder presentation is extremely dangerous because the baby must be forced by the attendants into a breech position. This forcing can rupture the uterus, which may cause the death of the infant and severe hemorrhaging in the mother.

Another dangerous problem that can occur during birth is anoxia. Anoxia can occur if the placenta detaches prematurely if the umbilical cord is pinched or tangled, if the infant's head is injured to the point of hemorrhaging, or if the mother has been too heavily sedated during labor. If there is a problem during birth, the child may be removed from the uterus by Cesarean section. Approximately 23% of all births in the United States are Cesarean sections.

Whenever possible, obstetricians use special surgical incisions in the uterus so that a woman who has had one Cesarean section may later deliver babies vaginally. With the old Cesarean technique (when a vertical incision was used), once the incision was made and the uterine wall weakened, it was necessary to have any future babies also delivered by Cesarean. In addition, some obstetricians have recommended that Cesarean sections not be used routinely if breech birth or labor problems begin. They argue that breech births for low-weight babies, especially if the obstetrician is skilled, may present no difficulty and that abnormal labor of and by itself is not sufficient cause for a Cesarean section. When it is necessary, however, Cesarean section can be a life-saver for both infant and mother.

Third Stage

The third stage of labor occurs following the exit of the infant, during which time the placenta (or afterbirth) is expelled.

Induction of Labor

What does it mean to induce labor?
Inducing labor means starting labor by artifical means. Labor can also be augmented, or sped up, if your spontaneous contractions aren't considered adequate to bring you into full labor.

Why might labor be induced?
You may need to be induced if the risks of prolonging your pregnancy are higher than the risks of delivering your baby right away. Reasons include (but are not limited to) the following:

• You are still pregnant two weeks past an accurate due date.
• Your baby isn't thriving or growing in the uterus.
• Your placenta is no longer functioning optimally and the uterine environment is no longer healthy.
• You have a chronic or acute illness, such as high blood pressure, diabetes, or kidney disease, that threatens your well-being or the health of your baby.
• If your waters breaks and labor does not start within a reasonable amount of time.

There are natural and synthetic methods of inducing labor. Some of the most common methods are:

• Artificially rupturing the membranes that surround the fetus. This procedure causes little discomfort and if the cervix is ready for labor, this alone might do the trick. In other cases, you might be administered the drug Pitocin as well.
• Stripping the membranes during a pelvic examination. This procedure is thought to stimulate the release of prostaglandin hormones which can help ripen the cervix. It can be done at an office visit and has been shown to reduce your chances of a postterm labor.
• Inserting a gel or suppository containing the hormone prostaglandin into the vagina to ripen the cervix. Often this procedure will stimulate contractions and move a woman into labor; if not, it is followed by intravenous Pitocin (see below).
• Inserting a Foley catheter into the cervix to ripen it. A very small balloon at the end of the catheter is inflated with water, putting pressure on the cervix and causing it to open and soften. When the cervix begins to dilate, the balloon falls out.
• Using Pitocin — a synthetic form of oxytocin — to induce labor. It's given intravenously through a pump to start contractions and used for the duration of labor.
• Stimulating your nipples to release your own natural oxytocin. Massaging the nipples can cause uterine contractions, but this technique would not be used to jump-start labor if it needed to be induced right away. Also, the fetus needs to be monitored during nipple stimulation since it can hyperstimulate the uterus, so don't try this at home.
• Administering an enema or drinking castor oil. Both stimulate the bowels and produce prostaglandins, which might help to induce labor.

Before you take steps to speed up labor, check with your doctor or midwife. Labor should only be induced under the supervision and advisement of your caregiver.