Each year in the United States, approximately one third of more than 4 million neonates are born by cesarean delivery. Indeed, the operation is the most commonly performed major surgery in this country in women aged 18 to 44 years (Boyle, 2012). It follows that the procedure is one of the most often used in modern obstetrics. Until recently, the term “cesarean section” was used to describe operative abdominal delivery, but “cesarean delivery” is considered more accurate for reasons discussed subsequently.

The concept of delivering 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 involved the birth of heroes or gods, demonstrating their superhuman qualities. At the same time, however, the mother was usually dying or dead at the time of birth (Thompson, 1955).

Francis Rousset introduced the idea of performing this operation for a living woman in the 16th century. He suggested several obstetric complications that were more horrific than the surgery 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 women who survived. He also reported that another successful pregnancy may follow the operation (Young, 1944).

In the 19th century, introductions of diethyl ether as an anesthetic by Morton and of carbolic acid antisepsis by Lister made the possibility of an abdominal operation 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 yielded 100-percent maternal mortality rates, mostly due to infection or hemorrhage (Sewell, 1993).

The first major surgical advance in cesarean delivery technique was introduced by Porro in 1876 (Miller, 1992). Influenced by the prevailing concept of not suturing the uterine incision, Porro introduced a technique in which the uterine fundus was amputated following the delivery of the fetus. The cervical stump was then marsupialized to the anterior abdominal wall. Although drastic by modern standards, the Porro technique resulted in a dramatic decline in maternal mortality rates (Speert, 1958). The Porro procedure is described in further detail in Chapter 26 (p. 419).

The era of the modern cesarean operation began when Max Saenger (1882) 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, he closed the uterus with two layers. He recommended silver wire for the deep suture and fine silk for the superficial serosa. Although the Saenger classical cesarean became the mainstay for the next half century, the Porro operation remained popular for many years. Indeed, in one series in 1922 from the eastern United States, 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 an extraperitoneal low-transverse uterine incision. He argued that this approach reduced blood loss and infection risk. Later, Kronig in 1912 emphasized that the superior results were obtained not because of the extraperitoneal approach, but because of the lower-segment 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).

Although other obstetricians advocated using a transperitoneal uterine incision, Munro Kerr (1926) recommended a semilunar transverse uterine incision with the curve directed upward. The general objection to this incision was the danger of extending into the uterine vessels at the edges of the incision. Kerr, however, argued that using careful technique the vessels could be avoided. The success of this uterine incision—still used today—along with the development of antibiotics and blood-banking techniques, has caused cesarean delivery to be one of the safest major surgeries performed today.

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 in such a fashion. This theory, however, lacks credibility since Caesar’s mother was still alive when he was emperor. Another oft-quoted possibility is from a Roman law—Lex Regia—that mandated that any pregnant woman 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. Yet another possible origin is from the Latin verb caedare, which 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).

In 2013, there were nearly 4 million births in the United States (Martin, 2015). Since 1996, the cesarean delivery rate had increased every year but peaked in 2009 at 32.9 percent of all deliveries (Fig. 25-1). It appears to have plateaued, and in 2013 the rate was slightly lower at 32.7 percent.

Influencing Factors

Several factors have contributed to the declining cesarean delivery rate. In the last few years, the obstetric community has focused on reducing elective inductions before 39 weeks’ gestation (American College of Obstetricians and Gynecologists, 2015a). The effort of this campaign is reflected in the gestational age at the time of a cesarean delivery. The overall decline in these induction rates likely contributed to the decreased cesarean delivery rate at 38, 40, and 41 weeks’ gestation (Martin, 2015).

Maternal characteristics also affect the cesarean rate, and race is one variable. In 2013, non-Hispanic blacks (35.8 percent) had a higher rate than either Hispanics (32.2 percent) or non-Hispanic whites (32.0 percent). Second, maternal age influences delivery route. And, as maternal age at the time of cesarean delivery increases, so does the rate of cesarean delivery. Specifically, in gravidas aged 20 years, approximately 1 in 5 babies are born by cesarean delivery. In those aged 40 years or older, 1 in 2 babies are delivered operatively. Yet another factor is maternal obesity. As the body mass index rises, so does the cesarean delivery rate (Kominiarek, 2010).

The cesarean rate is not uniform throughout the United States. In 2013, Utah had the lowest rate at 22.4 percent. Three other states had a rate of 25 percent or less: Alaska, Idaho, and New Mexico. The state with the highest cesarean delivery rate (38.9 percent) was Louisiana. Two other states, Mississippi and New Jersey, had rates approximating 38 percent. Most states mirrored the national trend of cesarean delivery rate decline from 2012 to 2013. In fact, Georgia was the only state with a higher cesarean delivery rate in 2013 compared with that in 2012. Delaware and Montana had the most significant rate drops (Martin, 2015). Significant regional variation is not unique to the United States and can be found in other countries (Hanley, 2010).

Comparative Data

The United States has one of the highest cesarean delivery rates of industrialized countries. Recent data from the Organisation for Economic Cooperation and Development (OECD) (2016) show that Israel has the lowest cesarean delivery rate at 15.4 percent. Three other countries reported rates less than 20 percent: Finland, Sweden, and Norway. Three countries, Turkey, Italy, and Poland, reported rates higher than the United States. In Turkey, almost 1 of every 2 babies is born by cesarean delivery. Similar data were reported from eight Latin American countries. Paraguay reported the highest cesarean section rate at 41.4 percent, whereas Nicaragua reported the lowest at 24.2 percent. The rate in Brazil parallels that of the United States at 32.2 percent (Taljaard, 2009).

Nonmedical Factors

Several nonmedical factors also apparently influence cesarean delivery rates. One example is the type of hospital or hospital system (Bailit, 2012; Maso, 2013). In selected populations, the practice model of individual labor and delivery units is associated with different rates. Also, university services with residents have a lower rate than private practice physicians (Barber, 2011). Obstetric units staffed by laborists and midwife-physician teams also report lower rates (Iriye, 2013; Nijagal, 2015).

The concept of an ideal cesarean delivery rate is enigmatic. The World Health Organization (WHO) has opined that a rate of 1 to 5 percent is necessary to avoid severe maternal morbidity and mortality, whereas a rate beyond 10 percent does not lower neonatal mortality rates. This would indicate that a minimum cesarean delivery rate should be 5 to 10 percent (Gibbons, 2010). In 1985, the WHO recommended that the upper limit be 15 percent. Although this figure was based on theoretic estimates, observational studies have confirmed this value (Althabe, 2006; Villar, 2006). Healthy People 2020 recommends a 10-percent reduction in low-risk cesarean delivery rates from 26.5 to 23.9 percent and a 10-percent decline in cesarean births in low-risk women following a prior cesarean delivery. The current percent of low-risk women undergoing repeat cesarean delivery is 90.8 percent, and thus the goal for 2020 is 81.7 percent (Office of Disease Prevention and Health Promotion, 2014).

In the United States, significant health care resources are spent for management of pregnant women and their newborns. Indeed, 25 percent of all hospitalizations in this country are pregnancy related (Werner, 2014). According to the Truven Health Analytics MarketScan Study (2013), cesarean births are 50 percent more expensive than vaginal routes and carry an average cost of $27,866 for commercial payers and $13,590 for Medicaid. If the cesarean delivery rate in the United States was 15 percent, as suggested by the WHO, then $5 billion would be saved annually (Center for Healthcare Quality and Payment Reform, 2013).

Before a reduction in cesarean delivery rates can be accomplished, the indications for primary surgery must be examined. Recent data regarding cesarean delivery rates are shown in Figure 25-1. A primary cesarean operation is defined as the first cesarean delivery regardless of the number of previous vaginal deliveries. These account for approximately 60 percent of all cesarean cases. After the first surgical delivery, however, the probability of a subsequent vaginal delivery approximates only 10 percent.

The most common indications for primary surgery are labor arrest (34 percent), nonreassuring fetal heart rate tracing (23 percent), and fetal malpresentation (17 percent). Other indications, such as preeclampsia (3 percent), multifetal gestation (7 percent), and maternal request (3 percent), account for the remaining fourth of all operations (American College of Obstetricians and Gynecologists, 2014a). At the same time, and as outlined by the American College of Obstetricians and Gynecologists (2015b), operative vaginal delivery rates have declined (Chap. 23, p. 387). But in general, these indications for cesarean delivery in the United States are similar to those from other countries (Gao, 2013; Stjernholm, 2010).

Very few absolute indications necessitate primary cesarean delivery. Some examples are complete placenta previa, uterine rupture, and cord prolapse without imminent delivery. Other indications, for example, labor induction, dystocia, or nonreassuring fetal status, are subject to provider interpretation. Thus, the rates for these indications are highly variable and should be modifiable as indicated in Table 25-1. A prime example is labor induction, which increases the cesarean delivery rate in nulliparas (Chauhan, 2012; Grobman, 2012). The rate of inductions in the United States reached an all-time high of 23.8 percent in 2010, but has begun to decline since then. Importantly, induction rates have declined at 36, 37, and 38 weeks’ gestation, and the largest decline has been at 38 weeks. Clearly, elective inductions, especially in women with an unfavorable cervix, should be avoided if the goal is to decrease the cesarean delivery rate.

Attempts have been undertaken to more closely study the physiology of normal labor as originally defined by Friedman (1955). More recent studies indicate that the latent phase is longer in oxytocin-induced labors and that the active phase may not begin as early as Friedman concluded (Harper, 2012). Specifically, 40 percent of women whose latent phase is 12 hours or more will eventually deliver vaginally (Rouse, 2011). Another prominent example comes from the widespread use of labor epidural analgesia, which appreciably prolongs second-stage labor (Sharma, 2004; Zhang, 2010).

The fetus presenting as a breech remains one of the most common indications for cesarean delivery. In 2000, a randomized clinical trial was done to compare vaginal breech delivery and planned cesarean delivery (Hannah, 2000). Perinatal mortality and neonatal morbidity rates were significantly lower in the planned cesarean delivery cohort. This study, coupled with the increasing lack of experience with vaginal breech delivery, has resulted in a cesarean delivery in 85 percent of breech presentations. As indicated in Table 25-1, an alternative is an external cephalic version (ECV), which is successful 50 to 60 percent of the time (American College of Obstetricians and Gynecologists, 2016). Management of the breech-presenting fetus is described in Chapter 21.

Subsequent Pregnancies Following Cesarean Delivery

For the woman who is an ideal candidate for a subsequent trial of labor after a cesarean delivery, the success rate for a vaginal delivery approximates 60 percent. And, when a trial of labor was common, overall cesarean delivery rates were at their lowest (MacDorman, 2011). Namely, the vaginal birth after cesarean delivery (VBAC) rate peaked at 28 percent in 1996. After this, it dropped and by 2004 reached a rate <10 percent, which persists today. Also shown in Figure 25-1, in the past decade, once a woman has had a primary cesarean delivery, over 90 percent will undergo a repeat cesarean delivery (Spong, 2012). In fact, repeat cesarean deliveries are now more common than primary operations. This is despite the results of a Consensus Conference by the National Institutes of Health that encouraged a more liberal policy for a trial of labor following one or two low transverse cesarean deliveries (Cunningham, 2010). Discussed earlier were the goals of Healthy People 2020 that include a 10-percent reduction in the rate of repeat cesarean deliveries in low-risk women. This goal translates to a VBAC rate that approximates 20 percent (Office of Disease Prevention and Health Promotion, 2014).

The decision for a trial of labor or elective repeat cesarean delivery is a risk-versus-benefits balance. And although there are both risks and benefits to the mother and fetus, these are not always parallel. The deciding factor frequently is the risk for uterine rupture with perinatal death or neurologic damage. According to the American College of Obstetricians and Gynecologists (2015c), the risk for an unpredictable uterine rupture with labor is 0.7 to 0.9 percent after one low transverse cesarean delivery, and it is 0.9 to 1.8 percent after two operative deliveries. A principal drawback to multiple cesarean deliveries is the risk for abnormal placentation in subsequent pregnancies. Placental accrete syndromes are discussed further in Chapter 27.

Regardless of the delivery route chosen for an elective induction or a repeat cesarean delivery, it is important for the woman to have completed 39 weeks’ gestation (American College of Obstetricians and Gynecologists, 2015a). Delivery between 37 and 39^0/7 weeks’ gestation poses an elevated risk of neonatal morbidity and mortality. The primary complications are respiratory-related, and as expected, rates of ventilator use and admission to the neonatal intensive care unit (NICU) are increased (Clark, 2009; Tita, 2009). Importantly, delaying an elective repeat cesarean delivery until 39 weeks does not increase maternal morbidity rates (Tita, 2011). In recent years, quality and safety committees have been effective in encouraging elective deliveries at 39 weeks or later (Martin, 2015).

During the past few decades, anesthesia for cesarean delivery has become a safe endeavor because of the availability of trained professionals who administer neuraxial blockades or general anesthesia. In its most recent report, the Centers for Disease Control and Prevention cited anesthetic complications as the cause of <1 percent of maternal deaths in the United States from 2006 to 2010 (Creanga, 2015). Analgesia and anesthesia are discussed in detail in Chapter 19 (p. 311).

Some of the most essential steps to successful cesarean delivery begin prior to surgery. Perioperative considerations include patient consent, laboratory testing, antibiotic prophylaxis, venous thromboembolism prevention, and anesthesia selection. These are topics are covered extensively in Chapter 18 (p. 291).

Intraoperatively, when preparing for a cesarean delivery, the surgeon, surgical assistant, and operating room personnel should observe universal bodily fluid precautions. Once adequate anesthesia is confirmed and presurgical “time out” completed, cesarean delivery begins with a vertical or transverse abdominal incision. The types of laparotomy incisions and indications for their use are discussed in Chapter 4 (p. 49). The current epidemic of obesity has led to emphasis on the importance of the type of abdominal incision for extremely obese women (Marrs, 2014). Following entry into the peritoneal cavity, the position of the uterus, the dome of the bladder, and character of the lower uterine segment are assessed to guide subsequent surgical steps.

Uterine Incision Choice

A low transverse uterine incision is performed in greater than 90 percent of cesarean deliveries. One primary advantage is the lower volume of blood lost by incision of the thinner lower uterine segment compared with that into the thicker muscle of the uterine corpus. Second, the risk of uterine incision scar rupture in a subsequent pregnancy is substantially less with low transverse hysterotomy.

A vertical uterine incision may be considered for either maternal or fetal characteristics. With the mother, access to the lower uterine segment may be challenging or deleterious. For example, a densely adhered bladder from previous surgery may preclude safe access to the lower uterine segment without great risk of cystotomy. In other scenarios, a leiomyoma may fill the lower uterine segment, or the cervix may be invaded by cancer. Massive maternal obesity can also preclude safe access to the lower uterine segment. Some cases of placenta previa with anterior implantation, especially those complicated by morbidly adherent placenta, can pose similar access problems. When the placenta is implanted in the lower uterine segment, the vasculature around it may be prominent. By performing a vertical hysterotomy, a surgeon can avoid the placenta and its feeding vessels. As discussed in Chapter 27 (p. 447), if an abnormally adherent placenta is suspected—placenta accrete syndromes—then the uterine incision should be made superior to the highest edge of the placenta. In some of these cases, the incision may extend through the fundus of the uterus and even posteriorly (Society for Maternal-Fetal Medicine, 2010).

In other instances, fetal indications dictate the need. At times, the lower uterine segment is not thinned and widened, that is, “developed,” sufficiently to accomplish an atraumatic delivery for the mother and fetus. The most common indication for a vertical uterine incision is a preterm fetus in a nonvertex presentation. And if necessary to accommodate the fetal head, a vertical incision can easily be extended upward. Another indication for a vertical uterine incision is the fetus with a back-down transverse lie. With this presentation, the fetal feet may be difficult to grasp through a low transverse incision and can lead to traumatic injury of the uterus or fetus. Intraoperative intraabdominal version to either breech or vertex presentation may avoid vertical uterine incision in this instance. Last, multifetal gestations or certain fetal malformations, such as severe hydrocephaly or conjoined twins, often require the greater operating room afforded by a vertical incision.

Regardless of the incision type, entry into the uterus must be performed carefully. The incidence of fetal lacerations approximates 1 to 2 percent (Pandit, 2013). Preventive steps to avert this are described in the next section. As a final note, if the woman has had a prior vertical uterine incision, another vertical incision is not necessary for a subsequent cesarean delivery.

Low Transverse Cesarean Delivery

Hysterotomy

Traditionally, once the abdomen is entered, a bladder flap is developed. For this, the visceral peritoneum overlying the lower uterine segment is incised to permit entry into the vesicouterine space. Dissection in this space divides the bladder’s connective tissue attachments to the lower uterine segment. The bladder can then be moved caudad and away from a planned hysterotomy.

More recent evidence suggests that a bladder flap may be unnecessary in many cases (Table 25-2). Without this step, the time from skin incision to uterine incision is shortened, and rates of intraoperative and postoperative complications such as blood loss, postoperative pain, or urinary tract infections are lowered. However, studies have been underpowered to determine if this approach raises the incidence for bladder injury or any long-term complications (Dahlke, 2013).

When a bladder flap is deemed necessary, the visceral peritoneum overlying the uterus is grasped with forceps and incised with Metzenbaum scissors just above the superior margins of the bladder and below the vesicouterine peritoneum reflection (Fig. 25-2). The vesicouterine peritoneum is then undermined laterally with scissor tips and incised to the left and to the right of the midline. If difficulty is encountered, the incision was most likely made above the vesicouterine peritoneal reflection, and here the parietal peritoneum is densely integrated with the myometrium. In this case, the position of the bladder should be reevaluated such that the incision can be made again but lower.

The inferior margin of the incised peritoneum is then grasped with forceps or a Kelly clamp and undermined with the forefinger. This maneuver results in the development of the potential vesicouterine space between the bladder and the lower uterine segment and creation of the bladder flap. If blunt dissection is performed, the dissecting forefinger should be directed with the fingertip exerting pressure on the lower uterine segment of the uterus rather than on the posterior surface of the bladder. This will minimize the risk of inadvertent blunt cystotomy. Care must also be taken not to dissect too far laterally where vessel injury can lead to profuse bleeding. If a patient has had a prior procedure, the bladder flap may be scarred and sharp dissection may be necessary to develop the potential space (Fig. 25-3). Again, caution reduces the risk of inadvertent cystotomy.