Cesarean Deliveries Level Off After 12-Year-Long Rise

Tinker Ready

June 27, 2013

The overall percentage of infants delivered by cesarean surgery leveled off between 2009 and 2011 after climbing for more than a decade, according to data from the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention.

An analysis by Michelle J.K. Osterman, MHS, and Joyce A. Martin, MPH, both from the Centers for Disease Control and Prevention’s NCHS, Division of Vital Statistics, Reproductive Statistics Branch, Atlanta, Georgia, published online today on the center's Web site, indicated that the overall cesarean delivery rate of 31.3% did not change between 2009 and 2011. However, the rate of full-term (39 - 40 weeks of gestation) cesarean deliveries continued to rise, going up 3% to 30.1% in those same 2 years.

The trend follows 12 years of consecutive increases. Between 1996 and 2009, the cesarean delivery rate rose 60%. During that period, the percentage of cesarean births increased from 19.7% to 31.3% for singleton births.

The report notes that new guidelines from the American College of Obstetricians and Gynecologists (ACOG) aim to reduce the number of non–medically indicated cesarean deliveries and labor induction before 39 weeks of gestation. The ACOG effort calls for improved perinatal care, hospital policies barring elective delivery before 39 weeks, and public education.

The cesarean surgery findings for the period between 2009 and 2011 vary by gestational week. The rate for early-term births at 37 weeks declined less than 1%, going from 33.1% to 32.8%. The rate at 38 weeks dropped by 5%, going from 33.8% to 32.0%. There was a 4% increase in cesarean birth at 39 weeks, going from 32.4% to 33.7%. The rate at 40 weeks remained the same during that 2-year time period.

The rates also varied by the age of the mother. Cesarean rates for births at 38 weeks fell by at least 5% for all maternal ages. Mothers younger than 25 years saw the largest drop, at nearly 7%, going from 26.5% to 24.7%. At 39 weeks, the rates were at least 1% higher in 2011 than in 2009 for all maternal age groups. For women aged 25 years and older, rates increased at least 3%.

The study did not look at multiple births, as the rate for those births is generally 2.5 times higher than the rate for singleton births.

"Declines in cesarean delivery rates at 38 weeks were widespread, occurring among all maternal age groups, all racial and Hispanic origin groups, and more than one-half of all states, " the authors summarize. "In contrast, the cesarean delivery rates for births at 39 weeks rose for all maternal age groups, all racial and Hispanic origin groups, and in nearly one-half of all states."

National vital statistics data show a lower percentage of all singleton births delivered at 38 weeks and a rise at 39 weeks. "This shift toward longer pregnancies is consistent with efforts to reduce nonmedically indicated deliveries for nulliparous, vertex, singleton deliveries before 39 completed weeks of gestation because of the greater risk of poor outcomes for earlier gestations," the authors write. Although efforts have mainly focused on labor induction, these changes may affect rates of cesarean delivery, as "women who have been induced are nearly twice as likely to be delivered by cesarean as women with noninduced, spontaneous labor."

Future research should focus on the broad effect of these changes on maternal and infant health outcomes, the researchers conclude.

"Changes in Cesarean Delivery Rates by Gestational Age: United States, 1996-2011." National Center for Health Statistics. Data brief 124. Published online June 27, 2013. Full text


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