Reasons for Dramatic Rise in Cesarean Births Revealed

Time trends for each indication were modeled to estimate the absolute and cumulative annualized relative risk of cesarean by indication over time, and the relative contribution of each indication to the overall increase in primary cesarean delivery rate.

The researchers found that the cesarean delivery rate increased from 26% to 36.5% between 2003 and 2009; half of the increase was attributable to a rise in repeat cesarean delivery in women with a prior cesarean birth, but an equal proportion was due to a rise in first time cesarean delivery. Relative contributions of each indication to the total increase in primary cesarean rate were nonreassuring fetal status (32%), labor arrest disorders (18%), multiple gestation (16%), suspected macrosomia (10%), preeclampsia (10%), maternal request (8%), maternal-fetal conditions (5%), and other obstetric conditions (1%).

The researchers found that factors such as slowly progressing labor and fetal heart rate concerns were the largest contributors. In relative terms, nonreassuring fetal status, arrest of dilation, multiple gestation, preeclampsia, suspected macrosomia, and maternal request increased over time, whereas arrest of descent, malpresentation, maternal-fetal indications, and other obstetric indications (such as cord prolapse and placenta previa) did not increase. The study was published in the July 2011 issue of Obstetrics & Gynecology.

"We found that more objective reasons, such as the baby being in a breech position and placenta previa, remained stable over time, while less objective reasons, such as slow progress in labor and concerns about fetal heart tracings contributed large proportions to the increasing primary cesarean delivery rate," said lead author Jessica Illuzzi, MD, of the department of obstetrics, gynecology and reproductive sciences.

"Despite speculation that the decreasing use of forceps and vacuum-assisted vaginal delivery have led to increasing cesarean delivery rates, our data shows that since 2003 the increase in cesarean for labor arrest disorders was manifested in the first stage of labor prior to full dilation when forceps or vacuum are not appropriate," added Dr. Illuzzi. "Elucidating the reasons for the rise in cesarean delivery can help us consider if the benefits of the surgery based on indication appropriately outweigh the known risks, costs, and longer recovery time."

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