United Nations experts say that high rates of caesarian births in developing countries are linked to greater rates of sickness and death for mothers and their newborns. The study was conducted in Latin America.
Rates of caesarian delivery are increasing worldwide, according to World Health Organization researchers. They rose from about five percent of births in industrial nations in the early 1970s to more than 50 percent in some regions of the world by the late 1990s.
The investigators say there are many reasons for the increase, including better surgical techniques, fewer complications and more demand, based on the perception of doctors and mothers that the procedure is safe.
But a study in the journal Lancet by the WHO researchers finds reason for caution. Data from 97,000 births in 120 hospitals in eight Latin American countries - Argentina, Brazil, Cuba, Ecuador, Mexico, Nicaragua, Paraguay, and Peru - show that hospitals with higher caesarian rates had higher rates of premature births and newborns who died.
Study leader Jose Villar says mothers suffered more complications in those hospitals, too.
"Women needed to stay more time in the hospital, more [blood] transfusions," said Jose Villar. "They needed to be admitted into the intensive care unit more, and they had more infections. Women needed more antibiotics after the C-section."
Caesarian births avoid vaginal delivery by removing the baby through an incision in the uterus. The procedure is often recommended when the fetus is distressed, when the mother's build makes normal birth difficult, when there are multiple births, or when the mother's blood pressure is dangerously high.
But Dr. Villar says the Latin American findings show how an effective emergency medical intervention can do more harm than good, when applied to healthy populations.
"We are not establishing any cut-off point," he said. "We are saying, 'Please, review your practice. In your place, be it in the U.S. or wherever, please open your eyes. You may be doing more harm.'"
Villar's team says in an industrial country, each one percent increase in C-sections costs more than $9 million. The researchers say the money could be put to better use to improve other areas of maternal and newborn care.
The World Health Organization researchers will later report results of a similar study in Africa, and conduct others in Asia and North America.