Chapter 20. Operative Delivery

An operative delivery refers to an obstetric procedure in which active measures are taken to accomplish delivery. Operative delivery can be divided into operative vaginal delivery and caesarean delivery. The last several years have seen a steady decline in the operative delivery with an increase in the caesarean section rate. In addition, vacuum-assisted vaginal delivery has become more common than forceps. Most recent data from births in the United States during 2005 indicate that the vacuum-to-forceps ratio is approximately 4:1. The success and safety of these procedures are based on operator skill, proper timing, and ensuring that proper indications are met while contraindications are avoided. This chapter explains how each procedure is performed, the indications and contraindications to the procedure, the potential complications, and how to minimize complications.

The obstetric forceps is an instrument designed to assist with delivery of the baby's head. The invention of the precursor to modern forceps is credited to Peter Chamberlin in the 1600s. It is used either to expedite delivery or to assist with certain abnormalities in the cephalopelvic relationship that interfere with advancement of the head during labor. The primary functions of the forceps are to assist with traction of the fetal head and/or to assist with rotation of the fetal head to a more desirable position.

Although forceps-assisted vaginal deliveries were once extremely popular, the most recent data demonstrate that only one-quarter of all operative vaginal deliveries are performed using forceps. The reverse was true approximately 10 years ago. In fact, many investigators are concerned that the use of forceps is becoming a lost art. The reasons often cited in contributing to the decline in the use of forceps are (1) medicolegal implications and fear of litigation, (2) reliance on caesarean section as a remedy for abnormal labor and suspected fetal jeopardy, (3) perception that the vacuum is easier to use and less risky to fetus and mother, and (4) decreased number of residency programs that actively train residents in the use of forceps. These factors have led to a cycle in which less teaching has led to a decrement in technical skills, an increased fear of litigation, and a resultant further decrease in the use of forceps.

The Obstetric Forceps

The obstetric forceps (Fig. 20–1) consists of 2 matched parts that articulate or “lock.” Each part is composed of a blade, shank, lock, and handle. Each blade is designed so that it possesses 2 curves: the cephalic curve, which permits the instrument to be applied accurately to the sides of the baby's head, and the pelvic curve, which conforms to the curved axis of the maternal pelvis. The tip of each blade is called the toe. The front of the forceps is the concave side of the pelvic curve. The blades are referred to the left and right according to the side of the mother's pelvis on which they lie after application. During application, the handle of the left blade is held in the left hand, and the blade is applied to the left side of the mother's pelvis. Conversely, the handle of the right blade is held in the right hand and inserted so as to lie on the right side of the mother's pelvis. When the blades are inserted in this order, the right shank comes to lie atop the left so that the forceps articulate, or lock, as the handles are closed.

Physicians have been modifying 1 or more of the 4 basic parts since forceps were first invented. Although more than 600 kinds of forceps have been described, only a few are currently in use (Fig. 20–2). Although it is beyond the scope of this chapter to discuss all the different varieties of forceps and their indications, a brief comment on the more common types of forceps is appropriate. Simpson or Elliot forceps are most often used for outlet vaginal deliveries, whereas Kielland or Tucker-McLane forceps are used for rotational deliveries. Piper forceps are used in the United States for delivery of the aftercoming head in vaginal breech deliveries. The pelvic and cephalic curve, shank, blade, lock, and handle are different for each type of forceps. These features determine the type of forceps that is best suited for the appropriate indication. For example, Piper forceps, which are specifically designed for breech deliveries, have a reverse pelvic curve compared to other forceps. Simpson forceps are suited for application to the molded fetal head, whereas Tucker-McLane forceps or Kielland forceps are more appropriate to the fetal head with little or no molding.

Indications & Conditions for Forceps Delivery

In each of the following indications for forceps delivery, it must be emphasized that caesarean section is an alternative procedure that should be considered depending on the prevailing circumstances. Recognizing the inherent risks of both procedures, the obstetrician must decide which operation (vaginal delivery or caesarean section) will be safer for the mother and baby.

The indications for forceps delivery are as follows: (1) nonreassuring fetal heart rate pattern, (2) shortening of the second stage of labor for maternal reasons, (3) prolonged second stage of labor not due to dystocia, and (4) delivery of the aftercoming head in a breech presentation. A prolonged second stage of labor has been defined according to parity. In a nulliparous patient, a prolonged second stage is defined as more than 3 hours with a regional anesthetic or more than 2 hours without a regional anesthetic. In a multiparous patient, more than 2 hours with a regional anesthetic or more than 1 hour without a regional anesthetic constitutes a prolonged second stage of labor.

In order for the patient to be considered a candidate for forceps-assisted vaginal delivery with a cephalic presentation, all of the following prerequisites must be met: (1) complete cervical dilatation, (2) ruptured membranes, (3) fetal head engaged with the fetal head position known, (4) empty bladder, (5) no evidence of cephalopelvic disproportion, (6) adequate analgesia, (7) caesarean section capability, and (8) an experienced operator.

Classification of Forceps Deliveries

In 1988 the American College of Obstetricians and Gynecologists redefined the classification of forceps. As discussed later, the same classification should be applied to vacuum delivery. This classification uses the leading bony point of the fetal skull and its relationship to the maternal ischial spines in centimeters as the point of reference. Each station of the fetal head refers to the relationship of the leading bony part of the fetal skull with respect to the ischial spines. The fetal head is said to be at 0 station when the head is at the level of the spines. When the head is above this level, the station is described as –1 through –5, corresponding to the number of centimeters above the level of the ischial spines. When the head is below this level, the station is described as +1 through +5, corresponding to the number of centimeters below the level of the ischial spines.

The classification of forceps is defined as follows:

1. Outlet forceps is the application of forceps when (a) the fetal scalp is visible at the introitus without separating the labia, (b) the fetal skull has reached the pelvic floor, (c) the sagittal suture is in the anteroposterior diameter or in the right or left occiput anterior or posterior position, and (d) the fetal head is at or on the perineum. According to this definition, rotation of the fetal head must be ≤45 degrees.

2. Low forceps is the application of forceps when the leading point of the fetal skull is at station +2 or greater and not on the pelvic floor. Low forceps have 2 subdivisions: (a) rotation ≤45 degrees and (b) rotation >45 degrees.

3. Midforceps is the application of forceps when the head is engaged but the leading point of the fetal skull is above station +2.

Only rarely should an attempt be made at forceps delivery above station +2. Under unusual circumstances, such as sudden onset of severe fetal or maternal compromise or transverse arrest, application of forceps above station +2 can be attempted while simultaneously initiating preparation for a caesarean delivery in case the forceps maneuver is unsuccessful. Under no circumstances should forceps be applied to an unengaged head.

Preparation of the Patient for Forceps Delivery

The patient must be placed in the dorsal lithotomy position and the bladder should be emptied. The legs should be comfortably placed in stirrups with the hips flexed and abducted. The abdomen and legs should be adequately draped, and the vagina and the perineum should be prepped in usual fashion. If conduction (spinal/epidural) anesthesia is to be used, it must be administered prior to the foregoing steps in delivery. If pudendal block or local infiltration is to be used, it should be administered after the preliminary examination has been performed and all is in readiness for delivery. An appropriate and effective anesthetic is essential to the performance of a forceps delivery.

The Preliminary Examination

Before the application of forceps, a careful examination if necessary to determine the following:

1. The position of the fetal head, which usually is easily determined by first locating the lambdoid sutures and then determining the direction of the sagittal suture. The posterior fontanelle is readily evident after the 3 sutures running into it are identified. If the most accessible fontanelle is found to have 4 sutures running into it, it is the anterior fontanelle and the position usually is occiput posterior. In the presence of marked edema of the scalp or caput succedaneum, both sutures and fontanelles may be masked, and the position can only be determined by feeling an ear and noting the direction of the pinna. It must be emphasized that if the position of the fetal head cannot be adequately determined, then forceps should not be applied.

2. The station of the fetal head, which is the relationship of the presenting part to the ischial spines, must be determined. In labor that proceeds swiftly without complications, such a determination usually is simple and accurate. However, when the first or especially the second stage of labor is prolonged and is further complicated by marked molding and a heavy caput, this relationship may suggest a false level of the head in the pelvis. If the head can be felt above the symphysis pubis, forceps should not be used.

3. The adequacy of the pelvic diameters of the midpelvis and outlet is determined by noting the following: (a) the prominence of the ischial spines, the degree to which they shorten the transverse diameter of the midpelvis, and the amount of space between the spine and the side of the fetal head; (b) the contour of the accessible portion of the sacrum and the amount of space posterior to the head usually based on the length of the sacrospinous ligament; and (c) the width of the subpubic arch. This kind of appraisal is neither needed nor feasible for outlet forceps, but is essential for indicated low forceps or midforceps.

Application of Forceps

A major concept to bear in mind is that the application of forceps should use finesse rather than force. Before the forceps are applied to the fetal head, a “phantom application” should be performed first. It is vital to inspect the forceps to ensure that they consist of a complete and matched set and that they articulate (lock) easily. Forceps should be applied in a delicate fashion in order to avoid potential injury to the vagina and perineum. The goal is for the blades to fit the fetal head as evenly and symmetrically as possible. The blades should lie evenly against the side of the head, covering the space between the orbits and ears (Fig. 20–3). It is important to emphasize that correct application prevents soft tissue and nerve injury, as well as bony injuries to the fetal head. After the forceps have been applied, they should articulate easily. If the forceps cannot be easily articulated, the forceps should be removed and a second attempt made. Once the forceps articulate, the following checks should be performed for delivery of an occiput anterior position before any traction is placed on the fetal head. (1) The sagittal suture should be perpendicular to the plane of the shanks. (2) The posterior fontanelle should be 1 fingerbreadth away from the shanks equidistant from the sides of the blades, and directly in front of the articulated forceps. (3) If fenestrated (open) blades are used, the amount of fenestration in front of the fetal head should admit no more than the tip of 1 finger. After these checks have been performed, then traction can safely be applied to the fetal head. Traction forces should be applied in the plane of least resistance and should follow the pelvic curve. This can best be accomplished by applying downward pressure on the shanks with outward pressure exerted upon the handle of the forceps. Once the fetal head begins to emerge out of the vagina, the forceps are disarticulated, and the head is delivered via a modified Ritgen maneuver. After delivery, it is important to ensure that no vaginal or perineal lacerations go unrecognized, paying particular attention to deep lateral vaginal sidewall (sulcal) lacerations. Lacerations, if present, should be repaired in customary fashion.

A more detailed step-by-step description of a forceps-assisted vaginal delivery in the occiput anterior position is as follows (Figs. 20–4 through 20–6). The left handle is held between the thumb and fingers of the left hand. Using 2 or 3 fingers of the right hand placed into the vagina, the blade is guided to its correct position on the left side of the fetal head (Fig. 20–4). This maneuver is repeated with the right hand and the right blade, using the fingers of the left hand placed into the vagina to guide the blade (Fig. 20–5). The handles are depressed slightly before locking, in order to place the blades properly along the optimal diameter of the fetal head (Fig. 20–6).

The forceps are designed such that they lock easily as the handles are closed if the application is accurate. If the handles are askew or if any force is needed to achieve precise articulation, the application is faulty and the position must be rechecked. If simple manipulation of the blades does not permit easy articulation, the forceps should be removed, the position verified (by feeling an ear, if necessary), and the blades reapplied correctly. After the 3 checks have been adequately performed, traction can be applied.

Obstetricians hold forceps for traction in different ways. One method is to grab the crossbar of the handle between the index and middle fingers of the left hand from underneath and to insert the middle and index fingers of the right hand in the crotch of the instrument from above. Another method is to grasp the handles with the fingers on the top of the handles or shanks and the thumbs on the bottom. Traction is made only in the axis of the pelvis along the curve of the birth canal. No more force is applied than can be exerted by the flexed forearms; the muscles of the back must be used, and the feet must not be braced. If a greater degree of traction is needed, the cause may be cephalopelvic disproportion, asynclitism of the fetal head, or an error in the evaluation of the pelvic diameters. The obstetrician then should reassess the possibility of successful vaginal delivery.

As the head begins to distend the perineum, both the amount and direction of traction must be altered. The farther the head advances, the less the resistance offered by both the pelvis and soft parts; hence, only minimal traction should be applied as the head is about to be delivered. The head negotiates the final position of the pelvic curve by extension, and the physician should simulate this movement by elevating the handles of the forceps more and more as the head crowns (Fig. 20–7). If the forceps are allowed to remain in place throughout delivery of the fetal head, the handles will have passed the vertical plane as delivery of the head is completed. It is preferable to remove the forceps as the head crowns in the reverse order of their application by first disarticulating the forceps and raising the right handle until the blade is delivered. The left blade is then removed in similar fashion. Early removal of the forceps reduces the size of the mass that must pass through the introitus and thus reduces the likelihood of lacerations or extensions of episiotomies. After removal of the forceps, the head may recede; however, if the forceps have not been removed too soon, the head can be delivered by the use of the modified Ritgen maneuver during the next contraction. Because rotations with forceps and vaginal breech deliveries are now rarely, if ever performed, it is beyond the scope of this chapter to discuss these techniques.

Danger & Safety of Forceps

Although the use of forceps has fallen into disfavor over the last few years, few studies have prospectively evaluated the safety of forceps. A number of injuries to both mother and baby can result from the use of forceps, some serious and even fatal. Maternal complications include lacerations of the vagina and cervix, episiotomy extensions involving third- and fourth-degree lacerations, pelvic hematomas, urethral and bladder injuries, and uterine rupture. In addition, blood loss and the need for blood transfusion are increased in forceps deliveries. The baby may sustain minor facial lacerations, forceps marks, facial and brachial plexus palsies, cephalohematomas, skull fractures, intracranial hemorrhage, and seizures.

Many of these serious injuries and many of the minor ones inflicted by obstetric forceps result from errors in judgment rather than lack of technical skill. Such errors include failure to recognize the essential conditions for forceps delivery and lack of an appropriate indication for the operation as outlined earlier. The potential for injury increases in the following settings: (1) intervention occurs too early, before maximal molding and descent have been achieved by the patient's voluntary efforts, (2) continued traction is used in the presence of unrecognized cephalopelvic disproportion, (3) errors in diagnosis of the position of the fetal head, and (4) unwillingness to abandon the procedure and perform caesarean section. Most reports clearly demonstrate that maternal and/or fetal complications are more common with midforceps than with low or outlet forceps. The perception of increased fetal and maternal risk has served as one of the major driving forces contributing to the widespread decline in the use of forceps.

The idea of using a suction device applied to the fetal scalp to help facilitate deliver of the fetal head originated in the 1700s. The first vacuum cup was not designed until 1890. As one could well imagine, the first types of vacuum devices were crude, resembling a toilet plunger. In fact, the vacuum device did not gain much popularity until Malmström introduced a metal vacuum cup in 1954. The most common type of vacuum in use today is a pliable, Silastic cup with a handheld pump and gauge that allow delivery of the proper amount of suction pressure to the fetal head to effect delivery. Two models are shown in Figures 20–8 and 20–9. The vacuum extractor works by allowing the external traction forces applied to the fetal scalp to be transmitted to the fetal head. The traction on the vacuum apparatus increases the forces of delivery and facilitates passage of the fetus through the pelvis. In order for delivery to be accomplished, both traction on the fetal scalp and compression of the fetal head occur.

Indications & Contraindications for Vacuum Delivery

With the exception of delivery of the aftercoming head in a breech presentation, the indications for vacuum use are similar to those of forceps: (1) nonreassuring fetal heart rate pattern, (2) shortening of the second stage of labor for maternal reasons, and (3) prolonged second stage of labor. In addition, as mentioned earlier, the classification of forceps deliveries is the same classification used for vacuum deliveries, and the prerequisites are similar. Contraindications for vacuum delivery include the following: face presentation, breech presentation, true cephalopelvic disproportion, congenital anomalies of the fetal head (eg, hydrocephalus), gestational age <34 weeks, an unengaged fetal head, fetal demineralization disorder (eg, osteogenesis imperfecta), and known or suspected fetal bleeding diatheses (eg, hemophilia). In addition, caution must be exercised when the estimated fetal weight is >4000 g.

Vacuum Application

Before the vacuum is applied to the fetal head, the patient is prepared and the initial patient examination is performed as discussed earlier with regard to forceps deliveries. Application of the vacuum is perceived by many to be simpler than the use of the forceps. Before application occurs, the vacuum system should be assembled to ensure that no leaks are present. The cup should then be inserted into the vagina by directing pressure toward the posterior aspect of the vagina. The objective is to place the center of the cup directly over the sagittal suture at the median flexion point located approximately 3 cm anterior to the posterior fontanelle. This cup placement should allow for adequate maintenance of flexion of the fetal head during the entire procedure. The following checks should be performed prior to application of traction to the fetal head. (1) No maternal tissue should be included under the cup margin. (2) The cup should be placed in the midline over the sagittal suture and not off to the side of the head.

After the cup has been appropriately placed on the fetal scalp, an initial suction is applied, and the cup edges are reexamined to ensure that no maternal tissue is trapped underneath the vacuum cup. While the cup is held firmly against the fetal head, the pressure is increased to approximately 100–150 mm Hg to maintain the cup's position. The cup edges should be reexamined. If no maternal tissue is found under the cup edges, the pressure is increased to 500–600 mm Hg at the beginning of the uterine contraction. As the mother pushes, traction is applied downward along the pelvic axis. If more than 1 contraction is necessary, the vacuum pressure can be decreased to low levels between contractions. The axis of traction is then extended upward to a 45-degree angle to the floor as the head emerges. Once the head has completely delivered through the vagina, the suction is withdrawn and the cup removed.

Effectiveness & Safety of Vacuum

Most reports demonstrate that the vacuum is effective, with a failure rate of approximately 10%. The following factors have been implicated in determining the effectiveness of vacuum delivery: cup design, shape, size, and traction site attachment, consistency and strength of vacuum, strength of maternal expulsive efforts and coordination with traction, fetal size and extent of cephalopelvic disproportion, station and deflection of the fetal head, and angle and technique of traction.

The safety of the vacuum has been called into question. In May 1998, the US Food and Drug Administration issued a Public Advisory Statement regarding fetal complications associated with vacuum delivery. The purpose of this statement was to advise practitioners that vacuum devices might cause serious or fetal complications when improperly used. As a result, the following recommendations were made. (1) The vacuum should be used only when a specific obstetric indication is present. (2) Persons using the vacuum should be experienced and aware of the indications, contraindications, and precautions. (3) Those who use the vacuum should read and understand the instructions for the particular instrument being used. (4) The neonatal care staff should be educated about the potential complications of vacuum. (5) Individuals responsible for the care of the neonate should be alerted that vacuum has been used. (6) All adverse reactions should be reported to the Food and Drug Administration.

Use of the vacuum has been associated with a variety of neonatal injuries ranging from benign superficial scalp markings to serious and potentially life-threatening intracranial hemorrhages. The most common neonatal complication is retinal hemorrhage, which may occur in as many as 50% of deliveries. Fortunately, the complication rarely has any clinical significance. Cephalohematoma involves bleeding beneath the periosteum and complicates approximately 6% of all vacuum deliveries. Because the bleeding is located under the periosteum, significant bleeding rarely results because of the inability of the blood to cross the sutures. Subgaleal hematoma, a more serious complication, occurs in 50 per 10,000 vacuum deliveries. The condition arises when bleeding occurs in the loose subaponeurotic tissues of the scalp. Because bleeding occurs above the periosteum, it is not contained by the sutures. Consequently, there is the potential for life-threatening hemorrhage. The subgaleal space actually extends from the orbits of the eyes to the nape of the neck. This potential space can accommodate over half of a newborn's blood volume. Intracranial hemorrhage occurs in approximately 0.35% of vacuum deliveries. It can be a catastrophic complication that includes subdural, subarachnoid, intraventricular, and/or intraparenchymal hemorrhage. These complications can be quite severe but fortunately are rare.

Most authorities agree that injury can be significantly decreased or eliminated if the following protocol is used. (1) Traction is applied only when the patient is actively pushing. (2) Applying torsion or twisting the cup in an attempt to rotate the head is prohibited. (3) The duration of time during which the cup is applied to the fetal head should not exceed 20 minutes. (4) The procedure should be abandoned after the cup has dislodged or “popped off” from the fetal head twice. It should not be applied a third time. (5) The procedure should be abandoned if there is no fetal descent after a single pull. (6) Neonatal staff should be present at the time of the vacuum delivery. (Note: This also applies to forceps deliveries.) (7) Under no circumstances should the operator switch from vacuum to forceps or vice versa. An excellent study examining neonatal injury associated with operative vaginal delivery clearly demonstrated that the greatest incidence of neonatal injury occurred in babies in whom both vacuum and forceps were used. The practitioner must be cognizant of the risk of shoulder dystocia, which is increased with instrumental delivery. Shoulder dystocia occurs more commonly with vacuum deliveries than with forceps deliveries. A simple ABC mnemonic for vacuum extraction is as follows:

• A: Ask for help, address the patient (obtain informed consent), anesthesia
• B: Bladder empty
• C: Cervix fully dilated
• D: Downward traction, shoulder dystocia
• E: Examine fetal head position
• F: Flexion point

A detailed and complete delivery note should accompany each operative delivery. The medical record must document the indication for the procedure, the fetal station and head position at the time of the application(s) of forceps or vacuum, the type of device used, the total application time, the number of applications and “pop-offs” if vacuum was used, and if unsuccessful, the subsequent mode of delivery. It would also be prudent to include a comment in the medical record that the patient was informed of the potential complications of operative vaginal delivery.

Somewhat surprisingly, relatively few randomized, prospective studies have compared vacuum with forceps. In surveying the medical literature, the following conclusions can be drawn. On the whole, the vacuum extractor is less likely to achieve a successful vaginal delivery than is the forceps. The vacuum is significantly less likely to cause serious maternal injury than is the forceps. Although the vacuum is associated with a greater incidence of cephalohematoma, other facial/cranial injuries are more common with forceps. In comparing Apgar scores, the trend is toward more low 5-minute Apgar scores in the vacuum group than in the forceps group. Thus, an overall reduction in severe maternal injuries appears to be the most immediate benefit associated with the use of the vacuum. However, at this time, which instrument results in fewer major adverse neonatal effects remains to be determined.

Although both forceps and vacuum have proved to be useful in assisting with vaginal delivery, the vacuum is quickly becoming the preferred instrument of choice. Both forceps and vacuum extractors are acceptable and safe instruments for operative vaginal delivery. While candidates should be selected on an individualized basis and counseled accordingly, the skill of the operator should also influence the decision to attempt an operative delivery as well as the choice of instrument. Each instrument, however, has inherent risks. While the vacuum has been primarily associated with immediate neonatal morbidity, long-term data do not suggest any increased risk of neurodevelopmental delay in children delivered by either vacuum or forceps. In order to minimize both maternal and fetal risks, the operator must be familiar with the indications, contraindications, application, and use of the particular instrument. Guidelines similar to those discussed in this chapter should exist in order to facilitate a safe and effective delivery. While maternal morbidity may be slightly higher with forceps delivery, it is overall low in comparison with the morbidity that may be associated with delivery by caesarean section. In an era in which caesarean section rates are climbing, one must consider all of the available delivery modes and individualize them accordingly for each patient in order to ensure the most efficacious and safest delivery experience.

Caesarean section or caesarean delivery refers to the delivery of a fetus, placenta, and membranes through an abdominal and uterine incision. The first documented caesarean section on a living person was performed in 1610. The patient died 25 days later. Since that time, numerous advances have made caesarean section a safe procedure. In the past 35 years, the rate of caesarean section has steadily increased from 5% to approximately 30%. Over this time, the maternal mortality ratio (maternal deaths per 100,000 births) has decreased from almost 300 to <10. The following factors are often cited as contributing to the increasing caesarean section rate: (1) lower operative vaginal delivery rates, (2) lower rates of vaginal births after caesarean section (VBAC), and (3) fewer vaginal breech deliveries. In order for the practitioner to perform this common operation safely, he or she must be aware of the indications, risks, operative technique, and potential complications of this procedure.

Indications

Caesarean section is used in cases where vaginal delivery either is not feasible or would impose undue risks to the mother or baby. Some of the indications for caesarean section are clear and straightforward, whereas others are relative. In some cases, fine judgment is necessary to determine whether caesarean section or vaginal delivery would be better. It is not practical to list all possible indications; however, hardly any obstetric complication has not been dealt with by caesarean section. The following indications are currently the most common.

Repeat Caesarean Section

A prior uterine incision from a myomectomy or previous caesarean section may weaken the uterine wall or predispose to rupture if labor is permitted. The initial dictum of “once a caesarean, always a caesarean” was held for many years. However, as multiple publications documenting the safety of VBAC began appearing in the literature, many physicians moved away from this long-held belief. In 2000, a national goal was set to lower the rate of repeat caesarean sections to 3% while increasing the VBAC rate to 35%. The major incentives that led to this change in philosophy were fewer delivery risks with vaginal delivery, less need for anesthesia, less postpartum morbidity, shorter hospital stay, lower costs, and the encouragement of earlier and often smoother interaction and bonding between mother and infant. As more and more VBACs were performed in less than ideal settings, more complications arose. There may be no greater obstetric catastrophe than a uterine rupture resulting in maternal and/or fetal death. In fact, there appears to be a trend back toward the belief of “once a caesarean, always a caesarean.” Suffice it to say, “once a caesarean, always a controversy.”

In general, patients who are the most suitable candidates for trial of labor after caesarean section (TOLAC) are those (1) with 1 prior low-transverse caesarean section, (2) who present in labor, (3) with nonrecurring conditions (eg, breech, abnormal fetal heart rate patterns, placenta previa in prior pregnancy), and (4) with a prior vaginal delivery. Patients who are not candidates for a TOLAC include women with a prior classical (vertical) uterine incision or prior myomectomy. If a trial of labor is to be conducted, the patient must be placed on continuous fetal heart rate and uterine activity monitoring, and a dedicated obstetrician and anesthesiologist must be immediately available to intervene in case uterine rupture is suspected. Prostaglandins for cervical ripening must be avoided, and oxytocin must be used in a judicious and conservative fashion, if at all. Current studies cite a maternal mortality rate of close to 1% in cases of uterine rupture and a perinatal mortality rate of approximately 50% in association with uterine rupture. Therefore, it is of utmost importance that equipment for both maternal and electronic fetal monitoring and appropriate obstetric and neonatal facilities are available. A large-bore intravenous catheter must be used, and blood for possible maternal transfusion must be available. Appropriate anesthesia, a fully equipped operating room, and obstetric and neonatal staff experienced in emergency care must all be immediately available.

Cephalopelvic Disproportion/Dystocia

Cases in which the fetal head is too large to traverse the pelvis should be managed by caesarean section. As discussed earlier, if the head does not engage during labor, operative vaginal delivery should not be attempted. Rather, caesarean section must be performed. Inlet disproportion should be suspected in the primigravida if the patient begins labor with the fetal head unengaged. In a significant number of these patients, the fetal head fails to engage, and caesarean section is indicated. Midpelvic disproportion may be suspected if the anteroposterior diameter is short, the ischial spines are prominent, the sacrospinous ligament is short, and the fetus is large. Outlet disproportion usually requires a trial of forceps or vacuum before a safe vaginal delivery is determined to be impossible.

Dystocia literally means “difficult labor.” This occurs when a patient's labor progresses and then either stops completely (arrests) or becomes prolonged (protracted). When either of these situations occurs during labor, the patient warrants careful reassessment, including evaluation of the labor pattern, contraction pattern, estimated fetal weight and fetal presentation, and evaluation of the pelvis. In other words, the 3 P's (power, passenger, and pelvis) must be adequate in order for a vaginal delivery to occur.

Abnormal Fetal Lie & Malpresentation

Transverse lie and breech presentations are common indications for caesarean section. The trend toward caesarean delivery for breech deliveries has been hastened by a large randomized trial comparing breech infants born vaginally versus those born by caesarean section; better outcomes were achieved after caesarean section. Although some still consider vaginal breech delivery to be an acceptable option, experience with the technique is largely disappearing from practice. External cephalic version is a reasonable alternative for some patients and can be attempted to convert the fetus to cephalic presentation. However, this procedure is successful in allowing vaginal birth in only 50% of cases.

Fetal Heart Rate Tracing Abnormalities

Fetal monitoring before and during labor may disclose fetal problems that otherwise would not be evident. As a result of continuous fetal monitoring, the number of caesarean sections performed for a “nonreassuring fetal status” has increased. Best estimates demonstrate that approximately 10% of caesarean sections are performed for this indication.

Other Indications

In addition to the indications discussed earlier, other conditions that may lead to caesarean section are placenta previa, preeclampsia–eclampsia if remote from term, placental abruption, multiple gestations, fetal abnormalities (eg, hydrocephalus), cervical cancer, and active genital herpes infection. One other indication that is becoming more prevalent is patient choice. The idea of primary elective caesarean section continues to increase in popularity and generate controversy.

Preoperative Preparation for Caesarean Section

The following steps are generally taken before caesarean section is performed. The patient is made aware of the indications for the caesarean section, the alternatives, and the potential risks, benefits, and complications. She then signs a form indicating that she has received the appropriate information and consents to the procedure (“informed consent”). An intravenous 18-gauge needle should be in place with an appropriate intravenous solution running before the operation begins. The patient is given an antacid to minimize the likelihood of aspiration during anesthesia. A Foley catheter is placed to allow for continuous bladder drainage before, during, and after surgery. Anesthesia is administered, and the abdomen is prepped. The patient is covered with sterile drapes. Tilting the patient slightly to the left moves the uterus to the left of the midline and minimizes pressure on the inferior vena cava.

Operative Procedure

Abdominal Incision

Opinions differ regarding the type of abdominal incision that should be performed. Most obstetricians use the transverse (Pfannenstiel) incision with or without transection of the rectus muscles because wound dehiscence is rare and because the cosmetic result is usually better. In cases in which the caesarean section must be performed urgently or emergently, especially in patients with prior abdominal surgery or marked obesity, the midline vertical suprapubic incision is preferred because it is much quicker and the exposure for expeditious delivery and resolving uterine bleeding (by hysterectomy, if needed) usually is better. In the presence of a prior lower abdominal scar, it is important to enter the peritoneal cavity at the upper end of the incision to avoid entering the bladder, which may have been pulled upward on the abdominal wall at the time of closure of the previous incision.

Uterine Incision

Before the uterine incision is made, laparotomy pads that have been soaked in warm saline and wrung out can be placed on either side of the uterus to catch the spill of amniotic fluid. The degree of dextrorotation should also be determined by noting the position of the round ligaments so that the uterine incision will be centered. Torsion should not be corrected; instead, access to the midline should be obtained by retracting the abdominal wall to the patient's right. The different types of uterine incisions will be discussed later.

Encountering the Placenta

If the placenta is encountered beneath the uterine incision, the operator should avoid cutting through it; otherwise serious fetal bleeding may result. If the placenta cannot be avoided, an incision can be made through it. However, the baby must be delivered as quickly as possible and the cord clamped immediately to prevent significant blood loss.

Delivery

The operator delivers the baby, and then the placenta delivers. Recent evidence has demonstrated that blood loss can be minimized by massaging the uterus to allow for spontaneous placental expulsion rather than by manually separating and extracting the placenta. After delivery of the placenta, the uterus should be massaged and oxytocin administered in a dilute intravenous solution at a rate sufficient to maintain a firm contraction. The uterine cavity is wiped clean with a sponge so as to remove any retained membranes. The uterus is exteriorized, and active bleeding sinuses are clamped with either Pennington clamps or ring forceps.

Closure of the Uterine Incision

The closure of the uterine incision is dependent on the type of incision that is made. In general, the entire thickness of the myometrium should be closed. In order to potentially decrease the likelihood of uterine rupture during a subsequent pregnancy, the uterine incision should be closed in 2 layers. The 2 types of uterine incisions used most often and discussed here are the classical uterine incision and the low-transverse uterine incision.

Classical Caesarean Section

This is the simplest to perform. However, it is associated with the greatest loss of blood and with a greater risk of uterine rupture with subsequent pregnancies when compared with low-transverse incisions. The currently accepted indications for classical caesarean section are placenta previa, transverse lie (especially back down), and preterm delivery in which the lower uterine segment is poorly developed. A classical caesarean section may be preferred if extremely rapid delivery is needed, because this type of incision may offer the fastest means of delivering the baby. Nonetheless, the hazards of this procedure must be weighed against the additional minute or so needed to dissect the bladder away from the lower uterine segment and make the transverse semilunar low-transverse uterine incision.

In performing a classical procedure, a vertical incision is made in the body of the uterus. A scalpel is used to enter the uterine activity, and the incision is enlarged with bandage scissors. The fetus is delivered through the incision. After the placenta and membranes are removed, the uterine defect is repaired with 3 layers of running, interlocking absorbable suture. Number 0 suture is recommended for the 2 deeper layers, and 2-0 suture is used for the superficial layer to reapproximate the serosal edges.

Low-Transverse Caesarean Section

Because the low-transverse uterine incision (Figs. 20–10 through 20–17) is associated with less blood loss and the risk of subsequent uterine rupture is less than with a classical caesarean section, this type of caesarean delivery is performed more frequently. After the peritoneal cavity is opened and the uterus identified, the bladder fold of peritoneum is picked up with tissue forceps and incised transversely. The bladder is bluntly separated from the anterior aspect of the uterus inferiorly for a distance of 3–4 cm. The bladder is held away from this area by a specially designed bladder retractor. A transverse incision is made through the anterior uterine wall with the scalpel. Using either bandage scissors or fingers, the transverse incision is extended in a semilunar fashion and extended superiorly at the lateral edges in order to avoid the uterine vessels.

If the maneuver can be easily done, the fetal presenting part is elevated with the hand, making sure not to flex the wrist, thereby increasing the possibility of extension of the incision inferiorly toward the cervix. If the head is located deep in the pelvis, the head can safely be pushed up by an assistant inserting a hand into the vagina to elevate the fetal head for ease of delivery. After the baby and placenta are delivered, the uterus is exteriorized and clamps are placed on the cut edges of the uterus in areas of significant bleeding from the uterine sinuses. The uterine incision is generally closed in 2 layers using number 0 chromic catgut or other absorbable suture. After adequate hemostasis has been achieved, the bladder peritoneum either is reapproximated with suture or is left in place. Before the uterus is returned to the peritoneal cavity, the adnexa should be inspected for the presence of any pathology, such as ovarian cysts. Some practitioners prefer to close the anterior peritoneum with absorbable suture, whereas others prefer to leave it alone. The fascia, subcutaneous tissue, and skin are reapproximated in standard fashion.

Complications

The most common complications that result from caesarean section are postpartum hemorrhage, endometritis, and wound infection. Administering prophylactic antibiotics and ensuring hemostasis prior to closure of the abdomen have helped decrease the incidence of these complications. New data are emerging that demonstrate a lower risk of endometritis when antibiotics are given prior to the skin incision when compared to after clamping of the umbilical cord. The major factors affecting healing of the uterine incision are hemostasis, accuracy of apposition, quality and amount of suture material, and avoidance of infection and tissue strangulation. It can generally be stated that the longer the operative procedure, the greater is the likelihood of postoperative complications. Disasters following caesarean section are rare. Some clearly are not preventable. Others are the direct result of faulty surgical technique, especially lack of attention to hemostasis, inept or ill-chosen anesthesia, inadequate blood product replacement or transfusion of mismatched blood, and delayed diagnosis or mismanagement of infection.

Unfortunately, little information about the integrity of a particular scar in a subsequent pregnancy is gained by inquiry into the presence or absence of postoperative infection and location of the incision. In a later pregnancy, pain in the area of the scar may suggest dehiscence. Approximately 50% of all ruptures of classical uterine scars occur before the onset of labor. The incidence of uterine rupture is approximately 4–9% of classical scars and 0.7–1.5% of low-transverse scars. Rupture of a classical scar usually is catastrophic, occurring suddenly, totally, and with partial or total extrusion of the fetus into the abdominal cavity. Shock due to internal hemorrhage is a prominent sign. Rupture of the low-transverse scar usually is more subtle and almost always occurs during active labor. The most common presenting sign (present in more than 80% of cases) is a change in the fetal heart rate pattern. A newly recognized finding of variable or late decelerations should alert the obstetrician. Additional findings that might signal uterine rupture include vaginal bleeding, abdominal pain (especially over the prior incision site), and loss of fetal station. A scalp electrode to ensure a continuous fetal heart rate tracing should be utilized as soon as possible in patients who are undergoing TOLAC. If uterine rupture is suspected, the patient must undergo surgery as soon as possible.

Perinatal Morbidity & Mortality

Although it may appear on the surface that caesarean delivery is the safest for the baby, this may not be entirely true. Although usually benign, transient tachypnea of the newborn is more common with caesarean section than with vaginal delivery. The risk of fetal hemorrhage and hypoxia is present when the placenta is encountered below the uterine incision and is inadvertently or purposely transected. There is also the potential risk for laceration of the baby at the time that the uterine incision is made. Fetal laceration is reported to occur on an infrequent basis at a rate of approximately 0.2–0.4% of all caesarean sections. The usual site is on the face, in the area of the cheek, but it may also occur on the buttock, ear, head, or any other body site under the incision. Therefore, it is of great importance that care is taken when incising the layers of the uterus. This is especially true in a prolonged labor, in which the uterus may be very thin. Because of the potential complications to the baby inherent with each caesarean section, each infant should be examined by a trained professional as soon as possible after delivery.

A major indication for caesarean hysterectomy is the inability to stop bleeding. The most common reason for performing caesarean hysterectomy is abnormal placental implantation, such as placenta accreta, increta, and percreta. As the caesarean section rate continues to escalate, these complications are becoming more common. Other indications for caesarean hysterectomy include intractable uterine atony, inability to repair a ruptured uterus, and large uterine myomas. Caesarean hysterectomy is a potentially morbid procedure because of increased blood loss and potential for injury to the bladder, ureter, or bowel.

The technical aspects of hysterectomy at the time of caesarean section are similar to those of hysterectomy in the nonpregnant patient except that all structures, cleavage planes, and pedicles are highly vascular. Therefore, there is significant risk for excessive blood loss and the need for the transfusion of blood products. In cases in which there is a suspicion that caesarean hysterectomy may need to be performed, the anesthesiologist and blood bank personnel should be informed. It is recommended that blood products (packed red blood cells and fresh frozen plasma) are available. Lastly, a vascular surgeon or gynecologic oncologist should be available to assist if needed. Studies have demonstrated that caesarean hysterectomy performed on a nonemergent basis is much safer than hysterectomy performed on an emergent basis. Specifically, injury to the bladder and ureter and the need for blood transfusions are more common when caesarean hysterectomy is performed emergently.