Yale Researchers Identify Reasons for Rise in Cesarean Births

The cesarean section (C-section) delivery rate in the United States has risen significantly over the past decade. Yale School of Medicine researchers have performed one of the first studies investigating factors attributing to this increase, with some of the highest rates of growth observed in Connecticut and Rhode Island.

They discovered that 50% of the increase was due to a rise in repeat cesarean delivery in mothers who had given birth previously through cesarean birth, but an equal percentage was because of a rise in first time cesarean delivery.

In such births, the researchers discovered that aspects such as slow labor and poor fetal heart rate were the largest contributors for the decision to perform a C-section.

Jessica Illuzzi, M.D., of the Department of Obstetrics, Gynecology & Reproductive at Yale University led the study. Illuzzi and her colleagues examined cesarean births on data gathered from over 30,000 births at Yale-New Haven Hospital between the years of 2003 and 2009.

"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 (>50%) to the increasing primary cesarean delivery rate," reported Illuzzi.

The researchers also established that the increase was partially due to C-sections being used in the events of twin pregnancies, heavier infants, and preeclampsia, regardless of the fairly stable rates of these conditions in the population during the course of the study. Illuzzi stated that this information "suggests that the use of cesarean for these indications is increasing.”

Further, the researchers analyzed some of the typical reasons for increasing cesarean rates. "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," reported the researchers.

Surprising to some may be the find that maternal-choice cesarean births, often criticized and considered a large factor for the increase in C-sections over the past decade, made up only 8% of the total increase in C-section delivery in the study.

"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," said Illuzzi.

This study was pre-released early online and will be released in the July issue of Obstetrics & Gynecology.