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The time that a woman spends in the second stage of labor -- when she pushes, then finally delivers her baby -- is among the most intense stretches of her life, and is monitored extremely closely. The American College of Obstetricians and Gynecologists says that first-time moms generally have three hours to push their baby out if they've had an epidural, two if they haven't, and beyond that, they're thought to be experiencing a prolonged second stage of labor. Healthcare providers may move for a C-section, or an assisted delivery with a vacuum or forceps.

But a new study found that when women were given just one more hour to push, C-section rates went down by roughly half. And while the investigation -- published in the March issue of the American Journal of Obstetrics and Gynecology -- is small and unlikely to fundamentally change medical norms any time soon, researchers say it offers a much-needed critique of potentially outdated standards.

"[The time recommendation] came from expert opinion from the 1800s," said Dr. Alexis Gimovsky, a fellow in maternal fetal medicine at Thomas Jefferson University in Pennsylvania, and an author on the study. "Since then, there's really only been retrospective data used to validate that guideline." In the 1950s, researchers looked over earlier data and found that women who delivered their babies within two hours had lower rates of infection and serious postpartum bleeding, for example. In 1955, another team concluded that most women without anesthesia give birth within two hours.

The new study included 78 first-time moms delivering at Thomas Jefferson University Hospital, who were randomly assigned to have either the usual time limit of three hours, or allowed an extra hour to push. (The researchers looked only at women who had epidurals, not because that's what they set out to do, but because they simply did not have any patients who did not get pain meds and who qualified for the study.)

“"There can be benefits to allowing women to labor longer."”

Overall, 43.2 percent of the women who were given the typical three hours to push ended up having a C-section.

But just 19.5 percent of the women who were given four hours had one.

"The study really showed what we've seen in practice for years, which is that there can be benefits to allowing women to labor longer," said Gimovsky. "We were excited to see that it dramatically reduced the risk of C-section in this specific group of women."

The researchers also found no evidence that giving women more time put them, or their babies, at greater risk -- though Gimovsky cautioned that the study was too small to truly capture potential harms. Prior research has found risks to mother and baby when labor goes on too long, she said, so this is an area that requires further investigation.

Of course, for many women and babies, C-sections are absolutely vital. The World Health Organization has long advocated that countries' C-section rates not exceed 10-15 percent of births, but a recent study found that maternal and infant mortality rates continue to decline in countries as C-section rates reach up to 19 percent. The surgery saves lives.

The aim of the new study is not to challenge that fact, but rather help ensure that the current guidelines most doctors rely on are based in clear, strong evidence. Currently, more than 30 percent of births in the U.S. each year are C-sections, and Gimovsky said that around 10-15 percent of those take place in cases where the second stage of labor has stalled.

And prior investigations have likewise examined how simply giving women more time in labor may help eliminate some surgical births. One found, for example, that women today tend to take longer in labor than 50 years ago. Why isn't yet understood. But as NPR reported, an implication of the finding is that "today's obstetricians may be rushing to do Cesarean sections too soon because they're using an out-of-date yardstick for how long a 'normal' labor should take."

“"It's OK to ask to see if you're a candidate for waiting longer."”

For now, pregnant women should feel empowered to talk to their care providers about their options, Gimovsky said -- understanding, of course, that there are times when intervention is necessary.