Laughing gas makes a comeback as option for pain relief in labor

ST. LOUIS – Shannon Hagerty was in labor for nearly nine hours when she asked for nitrous oxide. Her labor had stalled. For three hours, her cervix hadn’t dilated any further. She was exhausted and anxious.

“What it did was, it relaxed my body in between contractions, and that made the contractions more bearable,” said Hagerty, 32, of O’Fallon, Mo. “It allowed the tension to go out of my body, so when I had a contraction I could stay on top of it and manage the pain.”

Within a few hours, she gave birth to a baby girl at the Mercy Birthing Center without any medical interventions.

“I wanted to go the natural birth route,” said Hagerty, who was a first-time mom. “I didn’t want to be hooked up to machines and IVs.”

Nitrous oxide – what many know as laughing gas from the dentist office – is growing in popularity as a way to provide pain relief during childbirth. Just five years ago, only two centers in the U.S. offered nitrous routinely. Now hundreds of hospitals and birthing centers are using the colorless, odorless and nonflammable gas.

Midwives, whose model of care supports natural birth, have led the charge. In 2010, the American College of Nurse-Midwives published a position statement that encouraged the inclusion of nitrous oxide as an option for women in labor.

“There have always been women who have a desire to have a more natural childbirth, and that trend is growing,” said Dr. Patricia Bolster, an anesthesiologist at Mercy Hospital St. Louis. “I think people are looking for less invasive ways of managing their labor pain, and nitrous oxide is being pulled back off the shelf.”

Mercy began offering the gas in labor and delivery a year ago, and in September, Mercy started providing it in its midwifery care birthing center. The Birth and Wellness Center in O’Fallon, Mo., just purchased the equipment and will begin offering it soon. Other area hospitals are showing interest.

Nitrous oxide was first used for pain relief in labor in 1881 and became more routine in the 1930s and 40s. While it is still used frequently in the United Kingdom, Canada and Australia, it fell out of use in the U.S. as more powerful anesthetics such as the epidural became more favorable.

While epidurals can completely block pain; they require an IV, frequent blood pressure monitoring, continuous fetal monitoring and staying in bed. The loss of sensation often prolongs the pushing stage of labor, increasing the chances of vacuum extraction and forceps delivery.

By using a gas for pain relief, the woman can put the mask to her face and breathe the mixture of 50 percent nitrous oxide and 50 percent oxygen whenever she feels she needs it. The effect goes away within minutes.

“The mom holds the mask herself and has complete control,” Bolster said. “She can use it for a couple of contractions and then set it aside for as long as she wants.” An anesthesiologist does not have to be present.

Hagerty said having that power was important. “To have control over how I wanted to use it was really awesome,” she said. “It’s not something done to you. You hold up the mask yourself. You are controlling what goes in your body, and you are reacting to your labor.”

She never felt loopy or funny, she said, just more relaxed.

Nitrous was nicknamed “laughing gas” because its euphoric effect has caused patients undergoing dental procedures to act funny. That’s because it is used in higher concentrations in the dentist chair, and the patient’s mouth is also numb to pain.

The pain of labor, however, is no laughing matter.

“There’s too much stimulation. Labor is too uncomfortable for you to get silly with this amount of medication,” Bolster said. “You still are going to be very focused on your labor. You still are going to be very focused on managing your contractions.” Women feel mildly sedated, she said, “like a light buzz.”

Bolster warns that the gas does not block pain. It only helps the patient better handle the pain. “Some people when they try it, they are disappointed,” she said.

Bolster said nitrous oxide is used most effectively late in labor, when a woman’s tolerance can be wearing thin.

“It’s just that little extra, when they get to a point in their labor where they think, ‘Oh, gosh, I don’t think I can do it,’” she said. “But they are almost there, and then you give them that nitrous oxide, and they are able to get over that last hump.”

Use of the gas is restricted to four hours, but women rarely use it for that long, Bolster said.

Research shows using nitrous oxide during labor is safe, though it has not been studied extensively since 1996, according to a 2011 review of nitrous oxide by the American Society of Anesthesiologists. The gas has been used extensively in other developed countries for decades, however, with good safety outcomes for both mother and child.

Side effects are listed as dizziness, nausea and vomiting; but those are rarely experienced with the small doses allowed during labor, Bolster said.

Babies are shown to have normal Apgar and neurobehavioral scores, and are able to breast-feed normally.

And, no, husbands and partners cannot take a hit to help take the edge off.

“We do hear a lot of jokes about that. We make them ourselves too,” Bolster said. “But we actually take it very seriously. When someone is using it and a nurse or midwife is not with (the patient), we only allow one other support person in the room. We want to discourage that type of use.”