A report published Friday by the Centers for Disease Control and Prevention (CDC) offers some encouraging news about Caesarean-delivery trends in the United States.
After more than a decade of steady increases, the U.S. Caesarean-delivery rate remained essentially unchanged from 2009 to 2011.
The 2011 rate — 31.3 percent — is still far too high, according to many health officials and women’s health advocates, but at least it seems to be leveling off. In the previous 12 years, between 1996 and 2009, the C-section rate had climbed a troubling 60 percent, from 20.7 to 32.9 percent of all births.
In other words, about one-third of all babies are delivered by surgery in the United States. In fact, Caesarean sections are now the country’s most commonly performed surgery.
(This data refers only to the births of single babies. The C-section rate would be even higher if multiple births, such as twins and triplets, were included. Such births are almost 2.5 times more likely to be delivered by Caesarean section than single births.)
Caesarean deliveries are often necessary, of course, to preserve the health — or life — of mother or child. And although the procedure is relatively safe, it is still major abdominal surgery, and thus poses serious health risks. The risks for the mother include uncontrolled bleeding, blood clots and bowel obstructions. For the baby, the major risk is the development of a respiratory problem.
Although less than 3 percent of U.S. women elect to have a C-section delivery, a growing number of women are requesting to have their labor induced, sometimes a week or two before their baby has reached full term. Labor induction is a major factor behind C-sections. A 2010 study found that first-time mothers who had their labor induced were twice as likely as other women to end up having a C-section.
And early delivery, either vaginally or by C-section, is associated with more developmental problems for children. A 2012 study found, for example, that babies born during the 37th and 38th week of pregnancy tended to perform less well on academic tests at age 8 than children born between the 39th and 41st weeks, even after adjusting the data for the children’s birth weights and for social and economic factors. (Those results should be interpreted with caution, however, as the study was designed to show only an association between the two factors, not a cause and effect.)
Different trends for weeks 38 and 39
Most of the recent leveling off in the C-section rate described in the new CDC report is due to a more than 5 percent decrease in the rate among births at 38 weeks of pregnancy. According to the report, this drop is most likely the result of recent initiatives by the March of Dimes, the American College of Obstetrics and Gynecology and others to discourage elective delivery prior to 39 weeks.
Unfortunately, that 5 percent decrease was countered by a 4 percent rise in the C-section rate among births at 39 weeks. The CDC report does not offer an explanation for this increase.
It may be, however, that although some doctors and women have gotten the message that having a baby too early (at week 38) is not a good idea, they may still be OK with an elective C-section or having their labor induced for nonmedical reasons at week 39.
The CDC report also includes state-by-state data. Some 30 states, including Minnesota, experienced a drop in the C-section rate at 38 weeks. In Minnesota, the rate of Caesarean delivery at 38 weeks dropped by 6.9 percent, from 27.7 percent in 2009 to 25.8 percent in 2011. (In neighboring Wisconsin, the rate stayed essentially unchanged, at around 26 percent.)
No states, however, experienced a drop in the C-section rate at 39 weeks. But 23 states experienced an increase in the rate (including Wisconsin, which had a 4 percent increase, from 26.2 in 2009 to 27.4 in 2011). The rest of the states, including Minnesota, showed no statistically significant change in the rate.
To explain the United States’ overall high Caesarean-delivery rate, the medical community often points to the fact that more expectant women have conditions such as high blood pressure, diabetes or obesity that put their pregnancies in the high-risk category and thus more likely to end in a C-section. Physicians also cite concerns about liability and malpractice.
But, as I’ve noted here before, those factors don’t fully explain the increase. Nor do they explain the dramatic differences in C-section rates found across the country.
For example, University of Minnesota researchers reported earlier this year that women in the U.S. with private insurance are more likely to receive a medical intervention during childbirth, including a C-section, than women without insurance or who are covered by their state’s Medicaid programs.
In a second study, the U of M researchers found stunning variations in C-section rates among individual hospitals — from 7.1 percent to 69.9 percent. Even when only low-risk pregnancies were included in the analysis, significant hospital-by-hospital variations (2.4 percent to 36.5 percent) were still evident.
The authors of that study cited differences in medical practices as the likely driver behind the variations.
The CDC report can be read in full on the center’s website.