A major operation, each cesarean actually involves a series of separate incisions in the mother. The skin, underlying muscles and abdomen are opened first and then the uterus is opened allowing birth of the newborn.
There are two main types of cesarean operations, each named according to the location and direction of the uterine incision:
- Cervical–a transverse (horizontal) or vertical incision in the lower uterus, and
- Classical–a vertical incision in the main body of the uterus.
Today, the low transverse cervical incision is used almost exclusively. It has the lowest incidence of hemorrhage during surgery as well as the least chance of rupturing in later pregnancies. Sometimes, because of fetal size (very large or very small) or position problems ( breech or transverse), a low vertical cesarean may be performed.
In the classical operation, a vertical incision allows a greater opening and is used for fetal size or position problems and in some emergency situations. This approach involves more bleeding in surgery and a higher risk of abdominal infection. Although any uterine incision may rupture during subsequent labor, the classical is more likely to do so and more likely to result in death for the mother and fetus than a cervical incision.
Many factors account for rising cesarean birth rates. By the 1960′s, increasing emphasis was being placed on the health of the fetus. With declining birth rates and couples having fewer children, even greater attention was given to improving the outcome of pregnancy, and infant survival in general. The nation’s infant morality rate began to be seen as an international yardstick on the quality of health care.
At the same time, advances in medical care combined to make maternal death from cesarean childbirth a rare occurrence. The safer the procedure became, the easier it was to decide to perform the operation. As a safe alternative to normal delivery, the cesarean became a practical way to try to improve the outcome of difficult pregnancies.
Studies suggesting the benefit of cesarean birth in dealing with various pregnancy complications also led to more cesareans. Obstetricians came to favor surgery in pregnancies with difficult deliveries that formerly would have required the use of forceps. The diagnosis of “dystocia”, a catch-all term meaning difficult labor, was made more frequently and handled more often with the cesarean operation. Fetal distress during labor–a condition often resulting in a cesarean–was more apt to be detected with the introduction of electric fetal monitoring. Increasingly, physicians used the cesarean method to deliver infants in the breech position prior to birth, adding still further to the rising cesarean rate.
Another important contributing factor was the rising number of repeat cesareans. As the number of women having their first cesarean increased, the long-held tenet “once a cesarean, always a cesarean” led to rapid increase in the number of repeat cesarean births.
Having had a prior cesarean delivery is one of the two major reasons women have the operation today. (The other is the diagnosis of dystocia.) The consensus development panel found that the rate of repeat cesareans is likely to increase further if present trends continue. Currently more than 98 percent of women in the U.S. who have had a cesarean undergo a repeat cesarean for subsequent pregnancies.
This practice was begun in the late 1900′s to avoid the risk of uterine scar rupture and hemorrhage during labor. At that time the classical cesarean incision was most widely used and the cesarean birth rate was extremely low.
Physicians now know that the classical, low vertical and “inverted T” incisions have a higher rate of rupture than the low transverse incision now in general use. The low transverse cervical cesarean also has been shown to result in fewer cases of lasting health disorders or death among mothers and infants. Today, many women who had earlier low transverse cesareans safely deliver subsequent children vaginally.
In studying the issue, the consensus panel found that the risk of maternal death in a repeat cesarean is two times that of a vaginal delivery. In addition, the maternal mortality rate for repeat cesareans has not fallen since 1970. The group concluded that the practice of routine repeat cesarean birth is open for question, and that labor and vaginal delivery after previous low transverse cervical cesarean birth are of low risk to the mother and child in properly selected cases.
The panel recommended that:
- In hospitals with appropriate facilities, services and staff for prompt emergency cesarean birth, some women who have had a previous low transverse cervical cesarean may safely be allowed a trial of labor and vaginal delivery.
- The present practice of repeat cesareans should continue for patients who have had previous cesareans with classical, inverted T or low vertical incisions, or for whom there is no record or the type of incision.
- In hospitals without appropriate facilities, services and staff, the risk of labor for women having had a previous cesareans may exceed the risk to mother and infant from a properly timed, elective repeat cesarean birth. To allow patients to make an informed decision, they should be told in advance about the limits of the institutions offering this service.
- More adequate information should be compiled on the risks and benefits of trying labor in patients with previous low transverse cervical incisions.
- Institutions offering labor trials following low transverse cesareans should develop guidelines for managing those labors.
- Patient education on initial and repeat cesarean birth should continue throughout pregnancy as an important part of patient participation in making decisions about the delivery.
There is a continuing trend to use the cesarean method to deliver a “breech baby”–a fetus positioned in the womb to be born in some way other than the normal head first manner. Nationally, the proportion of breech positioned infants delivered by cesarean rose from about 12 percent in 1970 to 60 percent in 1978.
Breech positioning involves higher risks for the mother and child, regardless of whether the delivery is vaginal or cesarean. Cesareans are being selected more often in these cases to try to improve the outcome in the face of the increased risks. But the consensus group found scientific data in this area generally inadequate to make firm conclusions about desirability of one approach over the other.
Most clinical reviews suggest that the cesarean may involve less risk for the premature breech infant, but this may not be true for term breech babies. Several studies indicate vaginal delivery of the uncomplicated term breech infant is preferable because an elective cesarean birth involves risk significant complications for the mother and little or no decrease in the risk of infant death.
Deciding which method of delivery to use in these situations involves considering many factors. These include maternal pelvic size, size of the fetus, the type of breech position and the experience of the physician with vaginal breech delivery.
In general, the consensus panel concluded that the cesarean presents a lower risk to the infant than a vaginal delivery when the breech fetus is 8 pounds or larger, or when a fetus is in complete or footling breech position or when the fetus is breech with marked hyperextension of the head.
The group recommended that vaginal delivery of term breech babies should remain an acceptable choice when the following conditions exist:
- anticipated fetal weight of less than 8 pounds;
- normal pelvic dimensions and structure in the mother;
- frank breech positioning without hyperextended head; and
- delivery by physician experienced in vaginal breech delivery.
Dystocia is a catch-all medical term covering a broad range of problems which can complicate labor. The consensus group found that this diagnosis was the largest contributor to the overall rise in the cesarean rate, accounting for 30 percent of all cesareans.
Included under the dystocia, or difficult labor, diagnosis are the following three basic types of problems which may impede labor:
- abnormalities of the mother’s birth canal, such as a small pelvis;
- abnormalities in the position of the fetus, including breech position or large fetal size; and
- abnormalities in the forces of labor, including infrequent or weak uterine contractions.
The first two categories are well-defined areas. The physician usually recognizes size or position problems early; guidelines for appropriate obstetrical action are available; and the effects of the various approaches for mother and infant are reasonably well known.
The consensus panel agreed that the last category–forces of labor–is most in need of scrutiny and offers an opportunity for moderating the cesarean rate. Generally, this diagnosis occurs with low-risk infants of normal weight and size. Studies have not shown that infants in the group are better off with either cesarean or vaginal deliveries, although the maternal mortality rate for dystocia in 1978 was 41.9 deaths per 100,000 cesarean births compared with 11.1 deaths per 100,000 vaginal births.
The panel concluded that in handling a difficult or slowly progressing labor without fetal distress, a physician should consider various options before performing a cesarean. These include having the patient rest or walk around, sedating the patient or stimulating labor with a drug called oxytocin.
The panel recommended that because the diagnosis of dystocia is poorly defined and so prominent in increasing the cesarean rate, practice review boards in hospitals should include dystocia cases when conducting reviews. The panel also stressed the need for more research on the factors affecting the progress of labor.
Has The Use Of Electronic Fetal Monitoring Led To More Cesareans?
Another diagnosis accounting for the rise in cesarean birth rates is fetal distress. Occurring during labor, this problem can result in various complications, the most serious being fetal brain damage because of oxygen deprivation.
The use of electronic fetal monitoring techniques has led to an increase in the diagnosis of fetal distress but not necessarily to increase in cesarean deliveries, according to the consensus panel.
Because current data are insufficient on the possible risks or benefits of handling this condition with either cesarean or vaginal deliveries, the panel recommended studies to gather information on the outcomes of births involving fetal distress and development of new techniques to improve the accuracy of the diagnosis. These steps, the panel said, may be expected to improve fetal outcome and lower cesarean birth rates.
Because of a need for early delivery, certain medical problems in either the mother or fetus can lead to cesarean birth. Examples include maternal diabetes, pregnancy-induced hypertension, vaginal herpes infection, and erythorblastosis fetalis, a blood disease related to the Rh factor in the mother. This entire group, however, contributes only a small part of the cesarean birth rate increases.
The consensus panel said that in some of these situations vaginal birth would be a safe alternative if a more effective method of stimulating labor before term was available. The panel recommended research to develop such methods.
There are certain times when conditions in the mother or infant make cesarean delivery the method of first choice. By providing an alternate route of delivery, the procedure offers great benefit in situations when a vaginal delivery carries a high risk of complications and death.
A cesarean is usually used when an expectant mother has diabetes mellitus. Such women have a high risk of having stillborns late in pregnancy. In these cases, a slightly early cesarean helps prevent this occurrence.
The cesarean can also be a lifesaving procedure when the following conditions are present:
- Placenta previa–when the placenta blocks the infant from being born.
- Abruptio placentae–when the placenta prematurely separates from the uterine wall and hemorrhage occurs.
- Obstructed labor–which can occur with a fetus in the shoulder breech, or any other abnormal position.
- Ruptured uterus.
- Presence of weak uterine scars from previous surgery or cesarean.
- Fetus too large for the mother’s birth canal.
- Rapid toxemia–a condition in which high blood pressure can lead to convulsions in late pregnancy.
- Vaginal herpes infection–which could infect an infant being born vaginally, and lead to its eventual death.
- Pelvic tumors–which obstruct the birth canal and weaken the uterine wall.
- Absence of effective uterine contractions after labor has begun.
- Prolapse of the umbilical cord–when the cord is pushed out ahead of the infant, compressing the cord and cutting off blood flow.
The risks of any medical procedure are determined by examining the related mortality statistics showing death rates and morbidity figures showing complications, injuries or disorders linked to the event. These vary from hospital to hospital and from locale to locale.
Although maternal death during childbirth is extremely uncommon, national figures show cesarean birth carries up to four times the risk of death compared to a vaginal delivery. The maternal mortality rate for vaginal delivery in 1978 was about 10 deaths per 100,000 births. For cesareans, the rate was about 41 deaths per 100,000 births. (In some cases, maternal deaths indicated in these figures were caused by illness rather than the surgery.)
The morbidity rates associated with cesarean births are higher than with vaginal delivery. Because major surgery is involved, the chance of infection and complication is greater. The most common are endometritis (an inflammation of tissue lining the uterus) and urinary tract or incision infections.
Does Cesarean Childbirth Require Special Anesthesia?
The use of anesthesia during childbirth is unique because it requires attention to the infant about to be born as well as the mother. Although rare, anesthesia-related maternal deaths continue to occur. Most, however, are potentially avoidable.
There are three major anesthetic techniques for cesarean birth. Spinal anesthesia is widely used, although the use of lumbar epidural anesthesia is increasing. Both are considered “regional” anesthesia because they deaden pain in only part of the body without putting the patient to sleep. General anesthesia, which renders the patient unconscious, is often used in an emergency situation and with women who object to the spinal or epidural approach.
The consensus panel recommended that the types of anesthesia available should be discussed among the patient, obstetrician and anesthesiologist. Each approach has advantages and disadvantages. If possible, the report recommends, the patient should have the option of receiving regional instead of general anesthesia.
Infants delivered with elective cesarean surgery, especially if it is performed before the onset of labor, appear to have a greater risk of respiratory distress syndrome (RDS). This condition, in which the infant’s lungs are not fully mature, may result if an error is made in estimating the age of the developing fetus. Under these circumstances, an infant–who otherwise would have been healthy if allowed to develop fully–encounters the problems of prematurity when removed too soon by cesarean. These include RDS and other lung disorders, feeding problems and various complications which is some cases require a long hospital stay.
Measures and techniques to assess the maturity of the fetus and the degree of lung development are readily available in the United States. The consensus report stressed the need for improving physician and patient education about the safe and effective use of these techniques in planning for elective cesarean delivery. Respiratory distress is unlikely to be a problem, regardless of the type of delivery, if the infant is born at or near term.
Other factors must be taken into consideration when weighing the prospects of cesarean. Although there has been only limited research on the psychological effects on parents following a cesarean birth, it is clear that surgery is an increased psychological and physical burden compared to vaginal delivery. In limited follow-up studies of infants, there has been no evidence of an adverse psychological effect on infants born by cesarean.
In some hospitals, family-centered maternity care has been extended to cesarean deliveries. The presence of the father in the operating room and the closer contact between the mother and newborn in this approach appear to improve the cesarean process.
The consensus panel recommended strengthening the information exchange and education of perspective parents about the overall cesarean experience. They urged hospitals to allow fathers in the operating room when possible and to avoid routinely separating the newborn from its parents immediately following delivery.Tags: Cardiotocography, Breech birth, Caesarean birth, Caesarean section, Obstetrics