Using Laughing Gas to Relieve the Pain of Childbirth

By Melanie Plenda

The pain of giving birth has been likened to amputating a finger. While everyone's childbirth experience is subjective of course, it's safe to say it hurts. A lot. And though doctors and midwives can offer everything from birthing balls to epidurals to ease, dull, and numb that pain, one thing that hasn't been in the tool kit in the U.S. for decades is nitrous oxide. This colorless, odorless gas—the same “laughing gas” often administered at the dentist’s office—when inhaled causes the woman's body to relax and gives her a calm feeling.

Nearly 50 percent of women giving birth in Finland and Canada, a full 50 percent in Australia, and 60 percent in the United Kingdom, avail themselves of nitrous for pain relief, and have for generations. But even though it's cheap and easy to use, only 1 percent of U.S. hospitals were offering it in 2011. As of this writing, there are 19 hospitals and 14 birthing centers in the country offering or in the process of offering nitrous oxide during labor.

Discovered in 1771, nitrous oxide was first used during labor in 1881, but wasn't regularly used for that purpose until 1934, when a device was created allowing for self-administration. However, even though it was available, it just never caught on in the U.S. By about the mid-1980s it had completely disappeared from hospitals in the States and no one seems to know why.

"It's just never been a part of the regular regimen used in this country," says Bill Camann, an obstetric anesthesiologist at Brigham and Women's Hospital in Boston, which will offer nitrous for labor this year. "And you know, old habits die hard and people are set in their ways, and for no good reason."

The nitrous comeback has been sluggish. The reasons for that are varied, but come down to culture, turf, and money.

Though it's ubiquitous in dental offices, getting gas for labor is not like getting gas for a root canal. The machines used for labor are set to a 50/50 blend of oxygen and nitrous and can't be adjusted, whereas dental gas is delivered can be regulated and delivered in much higher concentrations, up to 70 percent.  At the 50/50 level used for labor, nitrous is not an anesthetic; it's simply an analgesic.

"If a woman uses nitrous she'll say 'I feel pain,’ but, she'll say, 'I just don't really care," says Elizabeth Kester, a registered nurse who manages the Women and Children's Health Services at Monadnock Community Hospital in Peterborough, New Hampshire, which was the first hospital in New England to offer nitrous. That ambivalence, is due to the dissociative effect of the gas, Kester says.  

Women using it in labor get nitrous oxide through a facemask or a mouthpiece. Just before a contraction they take a big breath in, which releases the gas. They then breathe out into the mask. And as long as they do it right, the machine then scavenges any nitrous out of that exhalation, saving the rest of the people in the room from sampling some of that heady elixir on accident.

In less than a minute, usually about 30 seconds, the woman will feel the effect of the gas, but as soon as she takes the mask off and takes a few breaths of room air, the gas clears her body.

There are plenty of reasons to favor nitrous for pain relief during labor. First, the sensation of being on nitrous falls somewhere between feeling nothing and feeling everything. It also gives the laboring woman a sense of control, since she is the one who determines when she needs the gas and when she doesn't.

"If a woman doesn’t like the way she's feeling with the gas, she can just take off the mask and it's gone," Kester says. "With narcotics or an epidural if a woman doesn't like the way it feels, she kind of out of luck."

Narcotics such as morphine or fentanyl take up to two hours to wear off and can leave a woman feeling drugged. And epidurals typically numb a woman from the waist down, restricting her mobility for several hours. Side effects from nitrous oxide can include nausea, dizziness, and drowsiness.

Nitrous is also relatively safe. Both narcotics and epidurals come with safety concerns, and epidurals have an increased risk of the mother needing medical interventions later in her labor, says Michelle Collins, associate professor and director of the nurse-midwifery program at the Vanderbilt University School of Nursing.

It's also, so far, thought to be safe for the baby, because the gas is filtered through the mother's lungs and not her liver, as narcotics are, says Judith Bishop, a professor in the department of obstetrics, gynecology, and reproductive sciences at the University of California, San Francisco. And though the gas does pass through the placenta, it's gone once the mother takes a breath of room air. There is one study, however, that's proving to be a sticky wicket for proponents of nitrous. The study, done on pregnant rats, showed that exposing the baby to gas in utero may cause long-term neurological effects after birth. However,  the study used far higher doses of nitrous for a much longer duration than any laboring woman would use.

So why aren’t U.S. hospitals offering it?

One reason is that epidurals provide better pain relief, says Edward Yaghmour, chairman of the American Society of Anesthesiologists (ASA) committee on obstetric anesthesia and an associate professor at Northwestern University. For years, epidurals have been the gold standard when it comes to pain management during labor. According to a 2004 study in the Oxford Journals of Medicine , 65 percent of women in the U.S. have received epidurals, while less than 25 percent of women had epidurals in the U.K. A 2008 study of 27 U.S. states by the Centers for Disease Control and Prevention showed similar results.  Even at UC San Francisco, the only hospital to offer nitrous continuously for at least 30 years, the epidural rate is about 75 to 80 percent.

"In America, there is a tendency to want the strongest thing," says Judith Rooks, a former epidemiologist at the CDC and certified nurse midwife. "Epidurals are the strongest thing."

Plus, Bishop says, nitrous was never meant to replace epidurals.

"They fill different niches," she says. "It adds a choice in an arena where we have very few."

In many hospitals, there is a debate over who will administer the gas. One of the benefits of nitrous, according to proponents, is that it is easy to administer and requires very little special training, unlike an epidural, which only anesthesiologists can administer.

So when nurse midwives started pitching the idea of bringing nitrous back as an option for women in labor, the intention was for nurses and midwives to administer it. After all, they administer narcotics, which arguably have more serious side effects. But some anesthesiologists balked at the idea, seeing nitrous as an anesthetic gas falling under their purview.

"It’s a little bit of a turf situation," Bishop says. "Anesthesiologists have, and rightfully so, always been involved with anything to do with anesthetic pain and pain relief. And I'm sure their first instinct is to want to be in charge and want to be in control of it."

Yaghmour agrees, saying anesthesiologists’ concerns are founded.

"First and foremost, there are patient safety concerns. Two patients—the mother and the baby," he says. "The administration of anesthesia care is complex and technically demanding, which requires the supervision of a physician. Physician anesthesiologists have up to 14 years of education and 12,000 to 16,000 hours of training, compared to 7 years of education and just over 1,600 hours of training for nurse anesthetists. There are also technical concerns and issues of airway and sedation specifically in pregnant patients."

But the amount of nitrous used during labor neither reaches the ASA-established levels of an anesthetic gas nor renders a woman unconscious, Collins says. The ASA and the American College of Obstetricians and Gynecologists issued a joint statement paper in 2010 saying that trained labor nurses should be allowed to participate in pain management.

So the turf question really amounts to who's going to get paid if nitrous becomes more widely used in American hospitals.  

"No one makes a lot of money when a woman uses nitrous oxide," Rooks says.

Costs for epidurals vary widely, anywhere from $250 to upwards of $1,000, depending on the hospital. Kester says nitrous costs about $15 per patient at her birth center.

As an anesthesiologist, Camann bristles at the idea that any hospital wouldn't offer something that was safe and could help ease a laboring woman's pain because of money.

"That would be a very typical kind of thing for a midwife to say," Camann says. "You know it's always, 'Oh it's just those greedy anesthesiologists, they don't want to use it because it affects their income,' and it's just absolutely not the case and I think you have to take that with a grain of salt when you're dealing with someone like a midwife."

But there are some hospitals where cost is at least a consideration, such as at Dartmouth Hitchcock Medical Center. Suzanne Serat, a midwife, explains that at DHMC, the anesthesiology department runs the nitrous program. As at many other hospitals, she says, labor and delivery is billed as one, all-inclusive charge for services.

At Dartmouth Hitchcock and other hospitals that run the nitrous program through anesthesia—or respiratory health in the case of Vanderbilt—if a woman wants nitrous, the nurse or midwife calls anesthesia. The anesthesiologist comes to the room when he or she is available, plugs in the machine, turns it on, tells the patient the side effects of the gas, shows her how to inhale and exhale, and leaves.

"It's too bad," Rooks says. "Because it adds time for a woman who needs it now. [Instead] she has to wait. It's silly. It's not done that way in other countries."

Bishop acknowledges that having anesthesia run a program that midwives and nurses could administer is a "concession," but she says she's doesn't care as long as patients have the option available to them. Collins has actually embraced the idea and uses it as a selling point when trying to convince hospitals to offer gas.

"At our hospital 60 percent of women did not use anything," Collins says, referring to narcotics and epidurals. "The hospital was not collecting money from them anyway. So by offering nitrous they are capturing a portion of the population they would have never gotten."

For now, she says she's hoping patients find out about it and start asking for it so more hospitals offer it as an option.

"Every day we hear from more hospitals looking at offering it," Collins says. "But what is still a barrier is that people don't know much about it. And you're always fearful of what you don't know."

This article available online at:

http://www.theatlantic.com/health/archive/2014/07/using-laughing-gas-to-relieve-the-pain-of-childbirth/374124/