Cesarean delivery (CD) is the most common major surgery performed in the United States. The Healthy People target for 2020 is a rate of 23.9% in low-risk full-term women, a much higher rate than the target rate of 15% for Healthy People 2010. Because vaginal birth after cesarean (VBAC) rates have declined and remain at low levels, the most effective approach to reducing overall morbidities related to CD is to avoid the initial CD. To synthesize the available information regarding factors leading to the first CD, including obstetric, maternal, and fetal indications for CD, labor management and induction practices, and nonmedical factors, this jointly sponsored workshop was convened in February 2012.
Numerous obstetric, fetal, and maternal factors are indications for primary CD and include malpresentation, multiple gestation, hypertensive disorders, macrosomia, maternal request, first- or second-stage arrest, failed induction, and nonreassuring fetal heart rate (FHR). Most indications depend on the caregiver’s interpretation, recommendation, or action in response to the situation. A CD that is performed without an accepted indication should be labeled as such, that is, a nonindicated CD. The term “elective CD” should be avoided.
Potentially modifiable factors include patient and physician attitudes and their perceptions regarding the risks of vaginal delivery compared with CD. Modifiable fetal factors are malpresentation, nonreassuring antepartum or intrapartum fetal surveillance, macrosomia, and malformations. Potentially modifiable obstetric factors include failed induction, arrest of labor, multiple gestation, preeclampsia, prior shoulder dystocia, prior myomectomy, prior third- or fourth-degree laceration, prior breakdown of repair, fistula, and marginal and low-lying placentation. Modifiable maternal indications for avoiding a first CD include obesity, infection, cardiovascular disease, inadequate pelvis, and patient request without maternal, obstetric, or fetal indications.
The overall likelihood of vaginal delivery is lower after labor induction than after spontaneous labor. Institutions should have a clear policy regarding labor induction, including a list of acceptable indications and definitions. Because the goal of labor induction is vaginal delivery, adequate time to enter into or progress in labor should be allowed, provided the mother and neonate are stable. The prudent use of labor induction, and the expectation that well-defined criteria be met before CD is performed for failure of induction or failure of progress in labor, may actually prevent many unnecessary first CDs. For example, use of a strict time threshold to define a failed induction of labor should not be used, and there is evidence that active labor does not occur until the cervix is at least 6 cm dilated with induction of labor.
The varying rates of CD among health care providers may result from different labor management styles. Admission of women in the early latent phase of labor is associated with higher CD rates. Whether admission in early labor itself increases the risk for CD or if women requiring admission earlier in labor are actually more likely to have an abnormal labor course is unclear. Hospital admission provides additional time to monitor labor progress and fetal well-being and to implement interventions to facilitate labor. Provider type may also be related to labor outcomes. Differences in the characteristics and expectations of women seeking different health care provider types may also affect the outcome. The same criteria for labor arrest and prolonged labor should be used regardless of health care provider or patient type.
The concept of a “protracted” first or second stage of labor is distinct from that of an arrest disorder. Progress in the first stage should not be based only on cervical dilation but must also consider changes in cervical effacement and fetal station. Progress in the second stage involves descent and rotation of the fetal head. Recognition of arrest of labor in the first or second stage allows reassessment of the maternal and fetal condition, counseling about the ongoing potential for successful vaginal delivery, and discussion of the maternal and perinatal risks of continued labor. In spontaneous and induced labor, the diagnosis of an arrest disorder should not be made before the patient has entered into the active phase.
Forceps and vacuum-assisted operative vaginal delivery may avert a CD when maternal expulsive forces are inadequate or emergent delivery is needed. Neonates delivered by operative vaginal delivery typically have a normal newborn transition period and normal long-term outcomes. Higher rates of operative vaginal delivery are often associated with lower CD rates, and vice versa, but a definitive cause-and-effect relationship has not been established. The decline in training and experience with operative vaginal delivery is an ongoing concern.
Electronic FHR monitoring is the primary method for assessing fetal status and is used to determine the mode of delivery in a complicated pregnancy. Guidelines defining appropriate candidates, the required frequency of auscultation, and criteria for conversion to continuous FHR monitoring should be available. Limitations in the interpretation of continuous FHR monitoring are interobserver variability in identifying patterns associated with fetal acidosis and the fact that many patterns have a low positive predictive value for adverse outcomes. Category I FHR tracings are strongly predictive of normal fetal acid-base status and are considered “normal.” Category III patterns are predictive of abnormal fetal acid-base status at the time of observation, are considered “abnormal,” and require prompt evaluation. The intermediate category II FHR patterns require attention but do not necessarily require immediate delivery; evaluation and continued surveillance and reevaluation are recommended. Until additional effective technologies become available, it is unlikely that the rate of CD for FHR abnormalities will be reduced. Hospitals should have quality control measures for operative deliveries with nonreassuring FHR as the indication.
The relative safety of CD has reduced apprehension regarding the risk of surgery, especially with borderline FHR abnormalities, protracted labor or arrest disorders, or after the development of obstetric or medical complications. Physicians and patients should be aware of the potential complications resulting from repeated surgeries for the mother and her fetus after the first CD. Time constraints for scheduling, operating room staff availability, and the inability to support prolonged inductions with scarce resources and space are part of the decision to progress to CD. Physician fatigue, workload, and sleep deprivation also affect decision making. The current medicolegal climate has made waiting for a vaginal delivery less attractive to many physicians. These factors are compounded by the belief among many patients that CD is safer for the fetus and ensures a normal outcome. Patient expectations, the medicolegal climate, and practice patterns regarding intrapartum management must be addressed to reduce the rate of primary CDs.
Although numerous factors contribute to the primary CD rate, the clinician’s ability to modify some of these and mitigate others is the first step toward lowering the primary CD rate. A CD rate of 30% or greater has huge effects on the medical system and on the health of women and children. Education regarding the range of what can be a normal labor course and the implications of first CD may allow women and their providers to avoid practices that increase the potential for unneeded first CDs.