Alternative methods such as water birth, acupuncture and relaxation techniques may help take the edge off the pain without those risks, but it's still unclear just how effective they are.

"It's important for a woman to be aware that there are a number of different measures that can help her," said Dr. James Neilson, an ob-gyn at the University of Liverpool in the UK, who led the new work.

While there is no one-size-fits-all, trying a low-risk, drug-free approach first makes sense, he added.

"I think there is a lot to be said for starting with simple methods and then working up if necessary," he told Reuters Health. "Clearly there is a lot of variation in the amount of pain that women experience during labor."

The new report is published by the Cochrane Collaboration, an international group of researchers that puts medical evidence through a rigorous review process.

Neilson and his colleagues decided to take a sweeping look at all previous reviews of clinical trials of labor pain management, both drug-based and not.

The researchers found 15 Cochrane reviews, including 257 trials, as well as three reviews of 55 trials done by other groups. But according to Neilson, there didn't seem to be any studies that compared alternative pain relief with standard painkillers.

There was solid proof that epidurals, currently the gold standard painkiller during labor, are effective. The same was true for so-called combined spinal epidurals and inhaled analgesia.

Epidurals were linked to a higher risk of assisted childbirth, in which doctors used forceps or similar instruments to deliver the baby. Women also were more likely to develop low blood pressure (which can slow down the babies heart beat) and to be unable to move their legs for a while.

But Dr. Mary Rosser, an ob-gyn at the Montefiore Medical Center in New York City, who was not involved in the new work, said side effects with epidurals are not common.

"In experienced hands… you should not have these issues," she told Reuters Health. "Serious complications are very, very rare."

According to 2008 US data, 61 percent of women who give birth get an epidural, during which painkillers are injected through a catheter into the back.

Neilson and his colleagues also found some evidence that water birth, relaxation, acupuncture, massage, local anesthetics and milder painkillers might ease the pain.

However, while those methods carry little risk of side effects, they have only been tested in a few, small studies.

For a range of other alternative methods -- including aromatherapy, hypnosis and transcutaneous electrical nerve stimulation (TENS) -- there simply wasn't enough evidence for the Cochrane group to make a judgment.

Rosser, also a member of the American College of Obstetricians and Gynecologists, said availability may be a problem for some alternative approaches.

"Not a lot of places offer the bathtub experience," she noted, adding that women shouldn't be afraid to ask for drugs if the pain is too strong.

"Every woman deserves the right to have pain relief during labor," she told Reuters Health. "A lot of times these days, less is more to women, they want to have a ‘natural plan' here. I always explain that that's fine, but just be open. For many women, the pain hits you like a ton of bricks."

SOURCE: The Cochrane Collaboration, online March 14, 2012.

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