Putting a halt to medically unnecessary cesarean sections could save more than $2 billion a year worldwide, a new study estimates. It has long been recognized that many countries have high C-section rates. In the U.S., C-sections now account for one-third of all deliveries -- an all-time high. The reasons are various. The rising rate of multiple births has played a role, since twins or "higher-order" multiples often need to be delivered by C-section. But experts generally agree that rates in the U.S. and many other countries are too high, since it`s unlikely that the rapid increase since the 1990s is due exclusively to medical need. There is no agreement on what the "correct" C-section rate is. But the World Health Organization has suggested that rates above 15 percent are probably too high. In the new study, researchers found that 69 countries worldwide top that 15 percent rate. On the other end of the spectrum, 54 countries had C-section rates lower than 10 percent -- which may be below what is medically needed. Then the researchers calculated the costs. In countries with high C-section rates, they estimate, getting the figure down to 15 percent would save $2.3 billion globally each year. In countries with low rates, the cost of bringing them up to 10 percent would be $432 million, the researchers report in the American Journal of Obstetrics and Gynecology. The findings paint a picture of the global "inequities" in C-sections, according to Drs. Jose Belizan and Fernando Althabe, who worked on the study. One implication is that a "better distribution" of resources could allow more women in poorer countries to get medically needed C-sections, said Belizan and Althabe, of the Institute of Clinical Effectiveness and Health Policy in Buenos Aires, Argentina. Recruiting professionals from high-rate countries to perform C-sections in low-rate ones -- or to train local health providers to perform them -- is one possibility, the researchers said in an email. Still, putting a dollar figure on the savings from reducing unnecessary C-sections is tricky. One issue is that this study assumed that the correct C-section rate is no higher than 15 percent. "And that is a very debatable point," said Dr. George Macones, who heads obstetrics and gynecology at Washington University in St. Louis and chairs the Committee on Obstetric Practice for the American College of Obstetricians and Gynecologists. "While cost is one factor to consider," Macones wrote in an email, "I think that we should be most concerned about doing what is in the best interests of our patients." There are other reasons to limit C-sections to only those cases where it`s the best course for the mother`s or baby`s health. Although the procedure is generally safe, it is still major abdominal surgery with inherent risks, like infection or too much blood loss. C-sections also boost the odds of certain problems with later pregnancies, including abnormalities in the placenta that can lead to severe bleeding during labor. According to Macones, a number a factors have likely driven the rise in the U.S. C-section rate. Some women request the procedure, for instance, so as to choose when they give birth or to avoid long labor. And obstetricians may be quicker to do them now than in years past. Worry over being sued should something go wrong during natural labor and delivery is one factor, according to Macones. But he said there are potential ways to bring the C-section rate to a more appropriate level. "I think the most important is to try to avoid first cesareans, and do them only when indicated," Macones said. One way to do that, he added, is to limit labor inductions to only cases where they are necessary. In inductions, doctors use medication or instruments to stimulate labor. But if labor fails to progress normally, a C-section may become necessary. Another way to limit C-sections, Macones said, is to do more vaginal deliveries in women who`ve had a C-section in the past. Repeat C-sections account for a large share of the U.S. total, even though experts say many women can successfully deliver vaginally after a past C-section. There is a chance the C-section scar will tear during labor, but it`s rare. Still, many U.S. hospitals do not offer those women the option of a vaginal delivery because they cannot guarantee a team on hand to perform an emergency C-section if necessary. Just how to curb high C-section rates remains the "million dollar question," Belizan and Althabe said. But Macones noted that last year, U.S. officials reported the first dip in the national C-section rate in more than a decade. In 2010, the rate was 32.8 percent, versus 32.9 percent the year before. Not a dramatic difference, but experts were hopeful that it pointed to a leveling off. As for poorer countries, Belizan and Althabe said there are numerous obstacles to women getting needed C-sections. High rates of home birth, too few hospitals and too few providers who can perform the surgery all remain barriers.