Cesarean Delivery

HISTORY

The concept of delivery of a living child through an abdominal incision has its origin in prehistoric times. References to these miraculous births are found in the folklore and mythology of both Eastern and Western cultures. Most of the early accounts of this mode of childbirth involved the birth of heroes or gods, demonstrating their superhuman qualities. However, the mother was usually dying or dead at the time of birth (Thompson, 1955).

Francis Rousset introduced the concept of performing an operation upon a living woman in the sixteenth century. He suggested several obstetric complications that were more horrific than the operation itself. In one example, the fetus had escaped into the abdominal cavity during labor and later caused an abdominal abscess that was debilitating to the woman. Next, he sought to establish the feasibility of the operation by giving an account of seven females who survived. He reported that another successful pregnancy may follow the operation (Young, 1944).

In the nineteenth century, introductions of diethyl ether as an operative anesthetic by Morton and of carbolic acid antisepsis by Lister made the possibility of an abdominal operation as an option for childbirth more feasible. Early success in the surgery was compromised by the widespread belief that once uterine muscle was incised it could not be safely sutured, principally out of fear of infection. Against this background, cesarean deliveries performed in Paris between 1787 and 1876 demonstrated 100 percent maternal mortality, mostly due to infection or hemorrhage (Sewell, 1993).

The first major surgical advance in the technique of cesarean section was introduced by Porro in 1876 (Miller, 1992). Influenced by the prevailing concept of not suturing the uterine incisions, Porro introduced a technique in which the uterine fundus was amputated following the delivery of the fetus and the cervical stump marsupialized to the anterior abdominal wall. Although drastic by today’s standards, the Porro technique resulted in a dramatic decline in maternal mortality (Speert, 1958).

The era of the modern cesarean began in 1882, when Max Saenger introduced the technique of suturing the uterus. He advocated performing a vertical incision in the uterus that avoided the lower uterine segment. After delivery of the infant and manual extraction of the placenta, Saenger closed the uterus with two layers. He recommended silver wire for the deep suture and fine silk for the superficial serosa (Saenger, 1882). The Saenger classical cesarean became the mainstay for the next half century. Nevertheless, the Porro operation remained popular for many years, and in one series from the eastern United States in 1922, 25 percent of abdominal deliveries were performed using Porro’s technique (Harris, 1922).

A uterine incision in the lower uterine segment was suggested as early as 1769 by Robert Wallace Johnson, but was not performed until a century later. One of the earliest advocates of its use was Fritz Frank who performed a low transverse uterine incision extraperitoneally. Frank argued that his extraperitoneal approach reduced blood loss and infection risk. In 1912, Kronig pointed out that better results were obtained not because of the extraperitoneal approach, but because of the uterine incision. He recommended a transperitoneal approach with a vertical incision in the lower uterine segment. He and others touted a maternal mortality rate of less than 4 percent (Young 1944). While other obstetricians advocated using a transverse uterine incision transperitoneally, Munro Kerr recommended a semilunar uterine incision with the curve directed upward in 1926 (Kerr, 1926). The general objection to this incision was the danger of extending into the uterine vessels at the edges of the incision. However, Kerr argued that using careful technique the vessels could be avoided. This uterine incision is still used today. With the subsequent development of antibiotic therapy and modern blood-banking techniques, cesarean section has evolved into one of the safest and most commonly performed major operative procedures.

The origin of the term “cesarean section” is obscure, but several different theories are promulgated. First, the popular belief is that Julius Caesar was born abdominally. However, recorded history indicates Julius Caesar’s mother was still alive when he was emperor. Because the understanding of anatomy and surgery were so crude in that era, this account of Julius Caesar’s birth is unlikely. Another possible origin is from a Roman law, Lex Regia, mandating that any pregnant female who died must have the fetus cut from her abdomen. When the ruler of Rome was referred to as the Roman Caesar, the law became known as the Lex Caesar. Finally, the Latin verb “caedare” means to cut. Children delivered from dead mothers were known as “caesones.” So, cesarean may simply mean to remove the fetus by cutting (Sewell, 1993).

CESAREAN SECTION RATE

Almost 4 million births occurred in the United States in 1996. Of these, more than 1 in 5 births (20.7 percent) were by cesarean delivery. While this rate of total cesarean births may appear high, this is the lowest recorded rate in the last decade (Ventura, 1998). The total cesarean birth rate in 1970 was 5.5 percent. This rate peaked in 1988 with 24.7 percent of all births occurring by cesarean delivery (Centers for Disease Control, 1995). During the last decade, the total cesarean rate has steadily declined (Fig. 15-1). The cesarean rate did increase in 1997 after declining for 7 consecutive years (Ventura and associates, 1999). Moreover, in preliminary data for 1998, Martin and associates (1999) reported that the cesarean rate for 1998 increased to 21.2 percent.

FIGURE 15-1. The total cesarean delivery (circles) and vaginal birth after cesarean delivery rates (squares) in the United States from 1989 to 1996. (Data from Monthly Natality Statistics Report 1998; 45(12).)

The overall decline in the total cesarean delivery rate is attributed to the declining primary cesarean rate and to the increasing number of vaginal births after previous cesarean deliveries. The primary cesarean delivery rate peaked at 17.5 percent in 1988, and steadily declined to 14.6 percent in 1996. This represents an 18 percent reduction in primary cesarean deliveries in the last decade. As the primary cesarean delivery rate declined, the number of vaginal births after a cesarean delivery (VBAC) increased. The VBAC rate in 1988 was less than 12.6 percent, but has increased to a high of 28.3 percent in 1996. The VBAC rate increased almost 65 percent in this time frame (Ventura and associates, 1998; Fig. 15-1).

The total number of cesarean deliveries are not uniform across the United States as one might expect. Significant regional variations exist. Birth certificate data from 1995 indicate a total cesarean section rate of 19.1 percent in the West, 19.3 percent in the Midwest, 21.7 percent in the Northeast, and 22.8 percent in the South (Curtin, 1997). The states with the lowest and highest total cesarean delivery rate in 1996 were Colorado (15.1 percent) and Mississippi (26.6 percent), respectively (Ventura, 1998). The primary cesarean section rate tends to parallel the overall rate. A large regional variation also occurs in the VBAC rate. The VBAC rate was lowest in the South (23.9 percent) and highest in the Northeast (31.4 percent) (Curtin, 1997).

The mode of delivery is also influenced by the demographics of the patient, physician, and hospital. Cesarean rates increase steadily with the age of the mother. Mothers 40–49 years of age were twice as likely to have a cesarean birth than was a teenager (31.6 percent vs. 14.5 percent, respectively; Ventura, 1998). Likewise, obese patients are almost twice as likely to have a cesarean delivery as compared to nonobese patients (Crane and associates, 1997). Both maternal and fetal medical conditions also increase the risk for an abdominal delivery. African American women have a higher cesarean delivery rate than either Hispanic or white females (Ventura, 1998; Aron and associates, 2000). Higher-income patients are more likely to have a primary cesarean delivery than are patients from lower socioeconomic groups (Gould, 1989; Aron and associates, 2000). Older, more experienced physicians perform significantly fewer cesarean sections for dystocia and have a higher percentage of forceps and vaginal breech deliveries (Berkowitz and associates, 1989). Physicians with a lower total cesarean delivery rate also manage labor more effectively to prevent cesarean deliveries for labor dystocia and by encouraging VBACs (Lagrew and Adashek, 1998). Teaching hospitals have a lower cesarean delivery rate than do nonteaching hospitals (Sanchez-Ramos and associates, 1994). Adjusted for acuity, hospitals with maternal fetal medicine specialists and a neonatal intensive care unit have a lower cesarean delivery rate (Clark and associates, 1998).

A number of international comparisons have been made with regard to cesarean birth rates. Brazil and the United States have the highest cesarean rates in developed countries, and Czechoslovakia, Austria, and Belgium have the lowest rates (Notzon and associates, 1987; Notzon, 1990). The United States has a higher rate for repeat cesarean delivery and dystocia than other industrialized countries, but has similar rates to other countries for breech delivery and fetal distress (Notzon and associates, 1994).

Pregnancy and childbirth account for approximately 40 percent of hospital discharges, so obstetric procedures contribute significantly to our national health expenditures. In 1996, the average total professional and hospital charges to insurance for an uncomplicated vaginal delivery was $7090. VBAC charges were $640 higher but were significantly less than the average cesarean delivery charge of $11,450 (Mushinski, 1998). Others argue that from a hospital perspective, the charges by the mode of delivery reflect the time a patient spends on a labor unit. An elective repeat cesarean delivery cost $7700 while a normal uncomplicated vaginal delivery cost $6800, a difference of only $900. A failed trial of labor and a cesarean delivery costs about $3000 more than a vaginal delivery. The difference in charges probably reflects additional cost of a patient with a prolonged labor (Sachs and associates, 1999).

The quality of care and the mode of delivery are important to clinicians, the public, and policy makers. Healthy People 2000, a project of the Department of Health and Human Services, set a goal of a 15 percent total cesarean delivery rate, a 12 percent primary cesarean delivery rate, and a 35 percent VBAC rate by the year 2000 (Healthy People 2000, 1990). How these targets were set is unclear as no evidence existed to support those specific goals. While some authors argue that they are attainable goals, others argue that those goals may jeopardize the safety and welfare of mothers and infants (Sachs, 1999; Flamm, 1998; and their associates). Nevertheless, various initiatives have been described that lowered the cesarean delivery rate without apparent ill effect. Clinical guidelines, confidential physician feed back, education regarding VBACs, and increased in-hospital attending coverage have been successful in decreasing the cesarean delivery rates in some institutions (Lagrew and Morgan, 1996; Poma, 1998).

INDICATIONS FOR CESAREAN DELIVERY

Most cesarean deliveries are performed for one of the following indications.

LABOR DYSTOCIA

Labor dystocia is the most frequent indication for primary cesarean delivery in the United States today, and a major cause of repeat cesarean deliveries (Gregory and associates, 1998). In general, cesarean deliveries should not be performed for dystocia in the latent phase of labor, and in the active phase, only after adequate uterine activity has been achieved (American College of Obstetricians and Gynecologists, 1995). Gifford and associates (2000), in a study of “lack of progress” in labor as an indication for cesarean delivery, reported that 68 percent of unplanned cesarean deliveries were for this reason. Moreover, 16 percent of the women were in the latent phase of labor, and the 36 percent who were completely dilated (10 cm) did not have a prolonged second stage. Recent data suggest that the current definition of active phase arrest, 2 hours without cervical change, may be too rigid. Extension of this interval may safely increase the number of vaginal deliveries (Rouse and associates, 1999).

There has been considerable debate on whether epidural analgesia causes longer labors and increases the number of cesarean deliveries for dystocia. This subject is discussed in Chapter 38.

Another area of controversy is the active management of labor. In a meta-analysis of cesarean delivery for dystocia, Glantz and McNanley (1997) reported a 34 percent decrease in cesarean delivery rates in nulliparas with active management of labor (OR 0.66; 95 percent CI 0.54–0.81). Moreover, adverse neonatal outcome was not increased.

NONREASSURING FETAL STATUS

Large prospective randomized clinical trials demonstrate that continuous intrapartum fetal heart-rate monitoring increases the cesarean delivery rate, especially in a low-risk population (Thacker and Stroup, 1999). Performing one or more measures, such as administration of oxygen, left lateral uterine displacement, correction of hypotension, discontinuation of oxytocin, decreasing uterine tone via use of a tocolytic agent, or amnioinfusion, may rectify abnormal fetal heart-rate patterns, and thus prevent an unnecessary cesarean delivery.

In diagnosing fetal hypoxemia and acidosis, external fetal monitoring has excellent sensitivity and negative predictive value (NPV). In other words, this testing modality is usually abnormal in the presence of hypoxia and acidosis (sensitivity), and excludes fetal hypoxia and acidosis very well (NPV). However, it is important to recognize the poor positive predictive value (PPV) of fetal heart-rate monitoring, which results in a high false-positive rate. In other words, the fetal heart-rate tracing may be abnormal, but the fetus is not hypoxic or acidotic. In the future, continuous pulse oximetry may increase the PPV of external fetal monitoring and may decrease the number of cesarean deliveries for non-reassuring fetal status (Dildy and associates, 1996).

BREECH PRESENTATION

Breech presentation occurs in 3–4 percent of all deliveries (Ventura and associates, 1998), and accounts for a significant number of cesarean deliveries. Although significant controversy regarding the best mode of delivery still remains, the cesarean section rate for breech presentation approaches 95 percent. This topic is discussed in detail in Chapter 8. It should be noted that cesarean delivery for a breech fetus is not risk free. The same maneuvers to extract a breech fetus at a cesarean section that is performed at a vaginal delivery must be performed. Birth injuries can and do occur (Cheng, 1993; Gifford, 1995; and their associates). In light of the present controversy, either mode of delivery may be acceptable for the term frank breech presentation (American College of Obstetricians and Gynecologists, 1986). However, even with planned vaginal delivery the cesarean section rate is about 50 percent in patients with a breech presentation. Therefore, the overall cesarean delivery rate is unlikely to decline significantly even with an aggressive approach to breech vaginal deliveries (Paul and Miller, 1995).

REPEAT CESAREAN DELIVERY

A patient may choose or the physician may recommend a repeat cesarean delivery without a trial of labor. In such cases, documentation of fetal maturity prior to delivery is essential. A repeat cesarean delivery can be performed at 39 weeks of gestation or later if one of the following criteria is met (American College of Obstetricians and Gynecologists, 1997):

1. Fetal heart tones have been documented for 20 weeks with a fetoscope or for 30 weeks by Doppler.

2. Thirty-six weeks have elapsed after a positive serum or urine human chorionic gonadotropin pregnancy test performed by a reliable laboratory.

3. A crown rump length obtained at 6–11 weeks supports the gestational age.

4. An ultrasound performed at 12–20 weeks confirms the gestational age determined by history and physical exam.

If an elective cesarean delivery is performed prior to 39 weeks of gestation, fetal lung maturation must be documented by amniocentesis. If a patient has poor dating criteria, awaiting the onset of spontaneous labor is another option. (American College of Obstetricians and Gynecologists, 1997)

VAGINAL BIRTH AFTER CESAREAN DELIVERY

Many factors influence a patient and her physician to proceed with an elective repeat cesarean delivery or a trial of labor after a previous cesarean delivery. Nonclinical factors, such as the setting in which the patient receives her health care, may influence the patient’s decision (Hueston and Rudy, 1994; Stafford, 1991). Physicians who have a cesarean rate less than 20 percent, who care for low-risk patients, and who are less than 54 years of age are more likely to offer a trial of labor (Goldman and colleagues, 1993). In contrast, patients may not opt for a trial of labor after a previous cesarean delivery because a scheduled repeat cesarean section may be more convenient.

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