Laughing gas is making a comeback in Twin Cities hospitals for women seeking to mute contractions and other pain during childbirth without narcotics or epidural anesthesia.

Once dubbed the “velvet hammer” because it was used to sedate women heavily in the 1950s and 1960s, laughing gas is now offered in more controlled doses — managed by women themselves during labor.

“They still feel what’s going on, but it’s not so bothersome to them. It kind of blunts the pain,” said Dr. Eric Locher, an obstetrician at Methodist Hospital in St. Louis Park, which started offering laughing gas, or nitrous oxide, last month.

Though used frequently in Europe, laughing gas was largely replaced in the United States by epidural anesthesia, which is typically injected by needle near the spine to numb the lower body. Epidurals are used in 61 percent of vaginal, single births, according to the latest count by the U.S. Centers for Disease Control and Prevention.

But interest in laughing gas from nurse midwives and other alternative providers, followed by research at Vanderbilt University and a handful of other institutions, has brought it back into mainstream U.S. medicine.

Women choosing the option receive a negative-air-pressure mask, which doesn’t dispense the gas until the patient secures it over her mouth and inhales. Pain relief from a single breath generally emerges in 30 seconds, and dissipates within three minutes, Locher said.

The Minnesota Birth Center, which provides midwife care and non-hospital births at its Minneapolis and St. Paul sites, started offering nitrous oxide earlier this year. Regions Hospital in St. Paul will add the option this fall.

Funnier and chattier

Brittany Howland was planning a water birth when she arrived at Methodist in the wee hours Friday morning for the delivery of her second child, but felt too tired and weak to proceed without some pain relief. As she prepared somewhat dejectedly for the epidural she wanted to avoid, she was given laughing gas to manage her contraction pains.

She joked with her husband that she seemed funnier and chattier after each puff before a contraction.

Three hours later, the Rosemount mother had given birth without the epidural because the gas was working so well.

“It’s an odd sensation,” she said. “You still feel the pain, but I think coping is probably the best word. I was still able to cope with it.”

Increased use of nitrous oxide in childbirth is emerging despite limited research evidence in its favor. Doctors at Vanderbilt University Medical Center conducted a review of existing studies for the federal Agency for Healthcare Research and Quality in 2012 and found that nitrous oxide provided less pain relief than an epidural, but didn’t present any additional harm or risk of birth complications to newborns.

However, the shallow pool of research should be evaluated against the decades of experience with nitrous oxide in countries that have superior fetal outcomes, said Michelle Collins, director of Vanderbilt’s nurse midwife program.

“In the U.K., 80 percent of women have it at birth,” she said.

Collins, who will visit Methodist later this year, said people need to distinguish this technique from the familiar use of laughing gas by dentists, who administer it continuously by a mask strapped over patients’ mouths at a concentration of 70 percent nitrous oxide to 30 percent oxygen. In childbirth, the concentration is only 50 percent, and women use it when they want.

“That self-empowerment, that self-control, leads to some of the satisfaction of it,” Collins said. “If you want to pick [the mask] up for every contraction, go ahead. If you only want to pick it up for the bigger ones, go ahead.”

Locher said some women prefer the more moderate and controlled pain relief of laughing gas to narcotic medications, which are potent but can leave patients “dopey,” and to epidurals, which reduce pain more completely but also leave them bedridden until the anesthesia wears off.

One complication of epidurals, research shows, is difficulty pushing, which can lead to increased use of forceps and other operative techniques to aid deliveries.

Studies have found complications from laughing gas, including nausea and dizziness in about one in 10 women. However, nitrous oxide is substantially cheaper than epidurals, which must be administered by anesthesiologists.

Engaged in the process

Giving up on her birth plan was difficult, Howland said, though she knew the ultimate goal was simply bringing home a healthy baby.

Laughing gas felt like a satisfying middle ground between the natural birth she sought and the epidural she had considered. Howland went home Saturday to spend the summer with her two children before she returns to work next fall as a school mental health therapist.

Inhaling from the mask helped her concentrate on the rhythmic breathing she was supposed to use anyway, she added.

“You’re staying engaged in the process, and yet it’s delivering something for you as well.”