Pregnant women tempted to induce labor for convenience rather than medical necessity may want to wait for nature to take its course.

Dr. J. Christopher Glantz at the University of Rochester School of Medicine found that inducing labor introduces a risk of 1 to 2 cesareans per 25 inductions that might have been avoided by waiting for spontaneous labor to begin.

While this risk to individual women is not particularly large, Glantz told Reuters Health that 1 to 2 cesareans per 25 inductions can quickly add up to tens of thousands of unnecessary cesareans over the course of millions of inductions.

While the procedures have become more common, C-sections are major surgeries, and carry risk of infection, bleeding, blood clots, and injury to other organs, Glantz emphasizes in a report in the journal Obstetrics and Gynecology.

The researcher analyzed birth certificate data for some 38,000 women from 13 hospitals in the Finger Lakes region of New York State from January 2004 to March 2008. He excluded women with scheduled or previous cesarean deliveries, or who had come to the hospital with ruptured membranes.

While previous studies have already shown that induced labor increases the risk for cesarean, Glantz examined how that risk might shift given a redefined comparison group.

He examined C-section rates after induction using three comparison groups: a week-by-week comparison of women induced to labor compared with those delivering spontaneously; women induced at a chosen week compared with women who delivered spontaneously after that week; and women induced at a chosen week compared with women who delivered spontaneously on or after that week.

In a nutshell, the study found that all labor induced groups faced increased risk for C-section, except for those women delivering after 39 weeks.

Glantz advises that pregnant women and their doctors may be better off waiting for spontaneous labor. Try to reserve interventions for situations where risk outweighs benefit, said Glantz, such as in cases of diabetes, high blood pressure, problems with the placenta, a baby that is not growing well, or a woman being 10 days past her due date.

SOURCE: Obstetrics & Gynecology, January 2010