"Nitrous oxide the laughing gas used in many dental offices is catching on in labor and delivery. Actually nitrous is making a comeback in U.S. maternity circles. It has remained a staple of childbirth in Canada Australia and Britain  Catherine Duchess of Cambridge the former Kate Middleton who welcomed her third royal baby Louis Arthur Charles last month reportedly has used it. But it basically disappeared in the United States in the s. American women preferred to be numbed below the waist with epidural anesthesia or at least that became the gold standard for pain relief. Now an estimated  U.S. hospitals and birthing centers offer nitrous  up from a handful less than a decade ago according to Porter Instrument in Hatfield maker of the leading nitrous oxide system. Midwives and others behind this resurgence emphasize that laughing gas is not anesthesia unlike epidurals or the other routine aid opioid painkillers. When nitrous is mixed  with oxygen and inhaled through a face mask it makes many women  not all  feel less anxious more relaxed and better able to deal with suffering. The gas works by increasing pleasuresignaling brain chemicals such as dopamine.  In labor half of the pain is feeling out of control said obstetriciangynecologist Laura Goetzl director of maternalfetal medicine at Temple University Hospital which began offering nitrous last month. Patients have been uniformly positive about having a choice. Some really liked it some didnt. It doesnt take the pain away but it creates a feeling of euphoria said midwife Julie Cristol clinical director of Lifecycle WomanCare and the Birth Center in Bryn Mawr which blazed the local trail by adding nitrous  months ago. Holy Redeemer Hospital in Meadowbrook also began offering laughing gas for labor last August. Nitrous has numerous advantages proponents say. Its simple for the woman to selfadminister takes effect in less than a minute and wears off just as quickly when she removes the mask and resumes breathing air from the room. Its also safe for the baby doesnt slow down labor and can be used at any point  including after the babys debut if a vaginal tear needs repair. Indifferent to the agony Labor pain is no laughing matter but women who use nitrous offer some funny reviews on blogs. I felt the contractions and pain but felt like I didnt really care Gemma James wrote on momshood https https If they had said they wanted to cut my leg off I would probably have agreed  well perhaps not really. If your pain is at  nitrous makes it about a  so mainly a distraction wrote a woman on babycenter.com. But it worked well for me. Annette Fisher  of Philadelphia also used the word distraction to describe her use of nitrous last month at Temple. Like many women who start with the gas she opted for an epidural when her pain intensified. The advantage she said was feeling fully aware of the birth of her daughter Amor  not doped up or groggy as with her first two births. I didnt want the narcotic it basically knocks out the experience Fisher said. The gas was very helpful. Midwives began championing the reintroduction of nitrous about a decade ago. The American Society of Anesthesiologists and the American College of Obstetricians and Gynecologists dont have official positions on its use. As midwives were always looking for lowtech options and there arent many for women in labor said certified nurse midwife Judith Bishop an emeritus professor of obgyn at the University of California San Francisco who has promoted nitrous. A reassuring safety record Nitrous comes with some caveats. It can cause nausea and dizziness. It also interacts with vitamin B so women with a deficiency of the nutrient shouldnt use the gas Goetzl said. But studies  and generations of use worldwide  have not found complications or longterm problems. Using nitrous to relieve labor pain is safe for the mother fetus and neonate Judith Rooks a certified nurse midwife and former government epidemiologist concluded in a medical literature review published in . Ironically about the same time the only company then making a labor nitrous system folded.  Part of the  system is a machine that scavenges any nitrous from the patients exhalation so other people in the room arent exposed to the gas. The setup also has a disposable face mask and tube. We acquired the rights to the system and brought it back in  said Michael Civitello a Porter Instrument salesman. Since then two other manufacturers have joined the growing market. While the Philadelphia area is a tiny part of that market so far several more maternity hospitals are considering nitrous Civitello said. Bishop the San Francisco midwife said I think some hospitals see it as a marketing tool so if the neighboring hospital has it theyd better have it. Insurance plans however generally dont cover it. The Birth Center in Bryn Mawr charges patients  to try nitrous and  to use it at will during labor. Temple and Holy Redeemer do not charge patients. We essentially give it away for free Goetzl said. Its really just because you want women to be happier and have higher satisfaction."