Safe Prevention of the Primary Cesarean Delivery
Safe reduction of the rate of primary cesarean deliveries will require different approaches to the range of etiologies for cesareans. For example, it is necessary to revise the definition of labor dystocia because recent data show that contemporary labor progresses at a rate substantially slower than what was historically taught. Additionally, improved and standardized fetal heart rate interpretation and management may have an effect.
Epidemiology/Incidence: In 2011, 1 in 3 women who gave birth in the United States did so by cesarean delivery. Cesarean birth can be life-saving for the fetus, the mother, or both in certain cases. However, the rapid increase in cesarean birth rates from 1996– 2011 without clear evidence of concomitant decreases in maternal or neonatal morbidity and mortality raises significant concern that cesarean delivery is overused. Additionally, studies have shown a 10-fold variation in the cesarean delivery rate across hospitals in the United States, from 7.1% to 69.9%, and a 15-fold variation among low-risk women, from 2.4% to 36.5%.
Risk factors/associations: In order to understand the degree to which cesarean deliveries may be preventable, it is important to know why cesareans are performed. In a 2011 population-based study, the most common indications for primary cesarean delivery included, in order of frequency, labor dystocia, abnormal or indeterminate (formerly, nonreassuring) fetal heart rate tracing, fetal malpresentation, multiple gestation, and suspected fetal macrosomia. Arrest of labor and abnormal or indeterminate fetal heart rate tracing accounted for more than half of all primary cesarean deliveries in the study population.
Complications: Childbirth by its very nature carries potential risks for both the mother and her baby, regardless of the route of delivery. The National Institutes of Health has commissioned evidence-based reports over recent years to examine the risks and benefits of both cesarean and vaginal delivery. For certain clinical conditions ––such as placenta previa or uterine rupture–– cesarean delivery is firmly established as the safest route of delivery. However, for the majority of pregnancies, which are low-risk, cesarean delivery appears to pose greater risk of maternal morbidity and mortality than vaginal delivery.
- Severe maternal morbidities––defined as hemorrhage requiring hysterectomy, hemorrhage requiring transfusion, uterine rupture, anesthetic complications, shock, cardiac arrest, acute renal failure, assisted ventilation, venous thromboembolism, major infection, or in-hospital wound disruption or hematoma–– are increased three-fold for cesarean delivery as compared with vaginal delivery (2.7% versus 0.9%, respectively).
There also are concerns regarding the long-term risks associated with cesarean delivery, particularly those associated with subsequent pregnancies. The incidence of placental abnormalities, such as placenta previa, in future pregnancies increases with each subsequent cesarean delivery, from 1% with one prior cesarean delivery to almost 3% with three or more prior cesarean deliveries. In addition, an increasing number of prior cesareans is associated with the morbidity of placental previa: after three cesarean deliveries, the risk that a placenta previa will be complicated by placenta accreta is nearly 40%.Thus, while the initial cesarean delivery is associated with some increases in morbidity and mortality, the downstream effects are even greater because of the risks from repeat cesareans in future pregnancies.
Prevention/ Management: Recommendations (Table 3)