A Caesarean section is major abdominal surgery with serious potential side effects. So the question of whether it should be performed when natural childbirth poses no threat to either mother or baby is controversial among obstetricians.
However, there have been few studies comparing C-sections with natural childbirth on the question of which is better for the baby, or mother.
Caesarean sections are still uncommon, but a study published this week in the British Medical Journal has found that the rate of elective C-section among American expectant mothers with uncomplicated pregnancies has increased by 67 percent since 1991, with a gradual rise from 1991 to 1996 and a rapid one thereafter.
The researchers, from Boston University in the United States, analyzed U.S. national birth certificate data and found that in 2001, there were 80,028 elective Caesarean sections performed in cases where there was no clear medical need.
That's a tiny fraction of America's four million annual births, but more than triple the 25,162 elective C-sections recorded in 1996.
Older mothers having their first child were the most likely to opt for a medically unnecessary C-section, the study found. Almost one-fifth of first-time mothers over 34 had such a delivery in 2001.
But the rate also grew among expectant mothers under 30, with five percent of them now having elective C-sections, the study found.
Similar trends are emerging in industrialized countries in Europe and South America. One study found a 90 percent Caesarean section rate among some regional populations in Brazil.
Caesareans can be safer for many mothers and babies. Fetal distress, breech babies, multiple births, or diseases that make labor risky for the mother can all be important reasons to have one.
Side effects, which can be life-threatening, include hemorrhage, infection, infertility and blood clots. Possibly more important, one C-section brings even more risks to future pregnancies.
Many women who opt for C-sections cite fears over pelvic floor muscle problems and resulting urinary incontinence among their reasons, but convenience and control over the schedule remains a dominant motivation.
"It is a concern," said Dr. Andrei Rebarber, an obstetrician specializing in high risk pregnancies at New York University Medical Center who was not involved with the study.
"Like everything else, the pendulum swings back and forth. We had the reactionary movement of the 70s and 80s about natural childbirth, people went to the middle ground in the 80s and 90s about getting pain relief but trying for vaginal birth," he said. "Now we're going back to this even more extreme interventional approach."
"It's in our desire for perfection and complete control over life," he Rebarber said.