Cesarean deliveries in women in the United States who were at low risk for the procedure declined overall during the 2 decades from 2000 to 2019, based on data from more than 40 million deliveries.
Although clinically indicated cesarean deliveries may improve outcomes for mothers and infants, “when not clinically indicated, cesarean delivery is a major surgical intervention that increases risk for adverse outcomes,” wrote Anna M. Frappaolo of Columbia University College of Physicians and Surgeons, New York, and colleagues.
The Healthy People 2030 campaign includes the reduction of cesarean deliveries, but trends in these procedures, especially with regard to diagnoses of labor arrest, have not been well studied, the researchers said.
In an analysis published in JAMA Network Open, the researchers reviewed delivery hospitalizations using data from the National Inpatient Sample from 2000 to 2019.
Births deemed low risk for cesarean delivery were identified by using criteria of the Society for Maternal-Fetal Medicine and additional criteria, and joinpoint regression analysis was used to estimate changes.
The researchers examined overall trends in cesarean deliveries as well as trends for three specific diagnoses: nonreassuring fetal status, labor arrest, and obstructed labor.
The final analysis included 40,517,867 deliveries; of these, 4,885,716 (12.1%) were cesarean deliveries.
Overall, cesarean deliveries in patients deemed at low risk increased from 9.7% in 2000 to 13.9% in 2009, then plateaued and decreased from 13.0% in 2012 to 11.1% in 2019. The average annual percentage change (AAPC) for cesarean delivery was 6.4% for the years from 2000 to 2005, 1.2% from 2005 to 2009, and −2.2% from 2009 to 2019.
Cesarean delivery for nonreassuring fetal status increased over the entire study period, from 3.4% in 2000 to 5.1% in 2019. By contrast, overall cesarean delivery for labor arrest increased from 3.6% in 2000 to a high of 4.8% in 2009, then decreased to 2.7% in 2019. Cesarean deliveries with a diagnosis of obstructed labor decreased from 0.9% in 2008 to 0.3% in 2019.
More specifically, cesarean deliveries for labor arrest in the active phase, latent phase, and second stage of labor increased from 1.5% to 2.1%, 1.1% to 1.5%, and 0.9% to 1.3%, respectively, from 2000 to 2009, and decreased from 2.1% to 1.7% for the active phase, from 1.5% to 1.2% for the latent phase, and from 1.2% to 0.9% for the second stage between 2010 and 2019.
Patients with increased odds of cesarean delivery were older (aged 35-39 years vs. 25-29 years, adjusted odds ratio 1.27), delivered in a hospital in the South vs. the Northeast of the United States (aOR 1.11), and were more likely to be non-Hispanic Black vs. non-Hispanic White (OR 1.23).
Notably, changes in nomenclature and interpretation of intrapartum electronic fetal heart monitoring occurred during the study period, with recommendations for the adoption of a three-tiered system for fetal heart rate patterns in 2008. “It is possible that current evidence and nomenclature related to intrapartum FHR interpretation may result in identification of a larger number of fetuses deemed at indeterminate risk for abnormal acid-base status,” the researchers wrote in their discussion.
The study findings were limited by several factors including the use of administrative discharge data rather than clinical records, the exclusion of patients with chronic conditions associated with cesarean delivery, changes in billing codes during the study period, and the inability to account for the effect of health factors, maternal age, and use of assisted reproductive technology, the researchers noted.
However, the results were strengthened by the large sample size and 20-year study period, as well as the stratification of labor arrest by stage, and suggest uptake of newer recommendations, they said. “Future reductions in cesarean deliveries among patients at low risk for cesarean delivery may be dependent on improved assessment of intrapartum fetal status,” they concluded.
Consider populations and outcomes in cesarean risk assessment
The decreasing rates of cesarean deliveries in the current study can be seen as positive, but more research is needed to examine maternal and neonatal outcomes, and to consider other conditions that affect risk for cesarean delivery, Paolo Ivo Cavoretto, MD, and Massimo Candiani, MD, of IRCCS San Raffaele Scientific Institute, and Antonio Farina, MD, of the University of Bologna, Italy, wrote in an accompanying editorial.
Notably, the study authors identified a population aged 15-39 years as low risk, and an increased risk for cesarean delivery within this range increased with age. “Maternal age remains a major risk factor associated with the risk of cesarean delivery, both from results of this study and those of previous analyses assessing its independence from other related risk factors,” the editorialists said.
The study findings also reflect the changes in standards for labor duration during the study period, they noted. The longer duration of labor may reduce cesarean delivery rates, but it is not without maternal and fetal-neonatal risks, they wrote.
“To be sure that the described trend of cesarean delivery rate reduction can be considered positive, there would be the theoretical need to analyze other maternal-fetal-neonatal outcomes (e.g., rates of operative deliveries, neonatal acidemia, intensive care unit use, maternal hemorrhage, pelvic floor trauma and dysfunction, and psychological distress),” the editorialists concluded.
More research needed to explore clinical decisions
“Reducing the cesarean delivery rate is a top priority, but evidence is lacking on an optimal rate that improves maternal and neonatal outcomes,” Iris Krishna, MD, a maternal-fetal medicine specialist at Emory University, Atlanta, said in an interview.
“Hospital quality and safety committees have been working to decrease cesarean deliveries amongst low-risk women, and identifying contemporary trends gives us insight on whether some of these efforts have translated to a lower cesarean delivery rate,” she said.
Dr. Krishna said she was not surprised by the higher cesarean section rate in the South. “The decision for cesarean delivery is multifaceted, and although this study was not able to assess clinical indications for cesarean delivery or maternal and fetal outcomes, we cannot ignore that social determinants of health contribute greatly to overall health outcomes,” she said. The trends in the current study further underscore the geographic disparities in access to health care present in the South, she added.
“This study notes that cesarean delivery for nonreassuring fetal status increased; however, nonreassuring fetal status as an indication for cesarean delivery can be subjective,” Dr. Krishna said. “Hospital quality and safety committees should consider reviewing the clinical scenarios that led to this decision to identify opportunities for improvement and further education,” she said.
“Defining contemporary trends in cesarean delivery for low-risk patients has merit, but the study findings should be interpreted with caution,” said Dr. Krishna, who is a member of the Ob.Gyn. News advisory board. More research is needed to define an optimal cesarean section rate that promotes positive maternal and fetal outcomes, and to determine whether identifying an optimal rate should be based on patient risk profiles, she said.
The study received no outside funding. Lead author Ms. Frappaolo had no financial conflicts to disclose; nor did the editorial authors or Dr. Krishna.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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