Ask the Midwife – Nitrous Oxide for Labor Analgesia

If you are like most pregnant women, you have been putting some thought into labor and what will happen during that process. Pain management is something that many women consider ahead of time. It is very common to have concerns about it: how much will labor hurt? Will I be able to manage it? What are my options for pain relief if the pain is too much for me? Will the options really help enough? Most women are a little nervous when thinking of these questions. Many women have heard of pain relief options such as the epidural or IV pain medication. There is a new option being offered for pain relief in labor at Lovelace Women’s Hospital; one that in fact has been in use for over a hundred years but is becoming more popular currently in the United States. This option is nitrous oxide, a pain reliever in the form of gas that is inhaled by the laboring woman.

Nitrous oxide has been used for many years in Europe for pain relief in labor, and in fact has been used in some U.S. hospitals for as long as 20 years. More recently, the use of nitrous in labor units in the U.S. has become more common, including in NM. You may be familiar with nitrous oxide, or “laughing gas” from the dentist office. The form given for labor is a bit different from the dentist office. It is standardized so that the laboring woman receives a mix of 50% oxygen and 50% nitrous oxide when she holds the mask to her face. Since the woman is in charge of holding the mask, she cannot overdose on the medication. She holds the mask to her face and begins breathing in about 30 seconds prior to the onset of the contraction, and continues to breathe in and out until the contraction is over. She then breathes room air in between contractions. I always advise women that it can take a bit to get into the rhythm of using the mask and inhaling the gas, so give it a little time to work. There are a small minority of women who feel no effect from nitrous oxide, and there are some who will use it and decide it does not control their pain well enough, so they move onto other options such as the epidural.

The use of nitrous oxide in labor is safe for the fetus. No heart rate changes are noted on the fetal monitor and as soon as the mother stops breathing the gas it is out of both her system and that of the baby. Side effects can occur in some women, including nausea and dizziness and less commonly, vomiting. Women who have certain medical conditions are unable to utilize nitrous oxide during labor. These include women with B-12 deficiency, pernicious anemia, Crohn’s disease and chronic malnutrition due to alcoholism.

The use of nitrous oxide in labor does not affect the length of labor, neither shortening it nor making it last longer. It is very easy to learn to use, works to relieve pain quickly, and has no negative effects on the fetus. We have had laboring women use nitrous oxide during pushing, by figuring out how to hold the mask with one hand and hold someone’s hand or pull up on their leg with their other hand. Nitrous can also be used for pain relief in the case of manual removal of the placenta (if the placenta does not deliver normally and has to be removed by the provider). This has advantages over IV pain medications as then the new mom will not be groggy or sleepy after the procedure. Nitrous can also be used during suturing, in the event of a laceration during delivery.

Should you choose to use nitrous oxide during your delivery you will be asked to sign a consent. That consent includes not sharing the mask with anyone in the room; your privilege to use it will be taken away in that case! We are very excited to be able to offer this option for pain relief to the women in our practice that deliver at Lovelace Women’s Hospital. If you have further questions about this option, please ask us during your prenatal visit. We hope you have a wonderful childbirth experience no matter what you decide on for pain relief. And remember, you may have an idea of what you want, but you can certainly change your mind at any time during labor. An open mind and flexibility go a long way during the labor process. Happy birthing!