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.