Why is the Cesarean rate so precipitously on the rise, from 21 percent of all American births in 1996 to 33.2 percent in 2007? The journal Obstetrics and Gynecology has the results of a new study that examines that question.
The Yale University Schools of Medicine and Public Health in New Haven, Conn., reacted to a spike in C-sections during births at Yale-New Haven Hospital between 2000 and 2002 by setting to work gathering comprehensive data on the 32,443 births that occurred there between 2003 and 2009, even while the hospital's C-section rate ballooned from 26 percent to 36.5 percent.
Not surprisingly, the study found that actual birth complications remained steady, while subjective judgments about the births changed.
The new study, presented at the February meeting of the Society for Maternal-Fetal Medicine, looks at the decision-making on the part of individual doctors that drove that increase.
"In this study, we examined physician-documented indications for Cesarean delivery at a major urban academic medical center in Connecticut, a state with one of the largest rate increases in the nation, to determine which specific indications contributed to the increase in our Cesarean delivery rate over a seven-year period," the researchers wrote.
First-time mothers accounted for half of C-sections during the study.
Indications for Cesarean delivery included "nonreassuring fetal heart tracing," an interruption in dilation, more than one fetus, pre-eclampsia, an especially large baby (which begins to be a concern just shy of nine pounds), and the mother's expressed desire for a Cesarean, the study's authors reported.
Complications like breech presentations, an interruption in the baby's progress into the birth canal and cord prolapse did not increase significantly over time, the study found.
Slow dilation and those unsatisfactory fetal heart rate reports displayed only slight increases over time but contributed to an outsize degree to the increase in C-sections, the study showed. Concern for the baby's well-being, based on fetal-heart monitoring, was the top indicator for a Cesarean section at Yale-New Haven Hospital during the period studied.
Maternal request, suspected macrosomia (a large baby), more than one fetus and pre-eclampsia also showed big annual increases as indications for Cesareans.
Interestingly, the C-section rate among patients of physicians in private practice was 33.2 percent. For "university patients," who received care from the hospital service's residents and faculty midwives, supervised by attending physicians, the rate was 25.6 percent. The rate for "high-risk" patients (whose care was provided by some of the same maternal-fetal specialists who supervised in the "university" cases) was 44.6 percent.