Among the medical reasons to induce are uterine infection or high blood pressure caused by the pregnancy (preeclampsia), among others.
While there are clear medical indications for C-sections, Fleischman suspects the "convenience" factor may be coming into play.
Experts have long suspected that the rise in C-sections was linked to an increased in preterm births, Fleischman said. "The challenge now is to sort out what percent of these C-sections are based on less than optimal medical indications," he said.
As for women requesting C-sections for convenience, Fleischman said that when they consider requesting early delivery before 39 weeks, they really need to understand that babies born before that time are at risk for problems.
The message of the study is clear, said Dr. Jennifer Wu, an obstetrician- gynecologist at Lenox Hill Hospital in New York City. "This is studying a large population, and it's warning doctors about the risk of an early delivery," she said.
All factors need to be balanced when trying to decide whether inducing an early delivery is wise, she said.
"If you are inducing early, it should be [for] a medical reason," Wu said. One example is a patient at risk of stillbirth, she said. "If you advise a patient, 'You are at risk for stillbirth, we would like to induce you early,' you have to make sure the [child's] lungs are mature."
If an obstetrician suggests delivering before 39 weeks, Fleischman advised women to ask why it is being suggested and what will happen if they do not. Those questions, in turn, he said, will hopefully help the physician and the patient make the best decision.
To learn more about preterm labor, visit the March of Dimes.
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