Reviewed & Vetted by Dr. Nazaneen Homaifar, Seven Starling Medical Director, Board-Certified OB/GYN
Nitrous oxide analgesia, also known as “laughing gas,” is a safe, effective, and noninvasive form of pain management available in many birth settings. Most people who use nitrous oxide during labor say that they were satisfied with the amount of pain relief it provided, and that they would use it again in future labors. Read on to learn all about nitrous oxide during labor:
- What is nitrous oxide?
- How does nitrous oxide work?
- Side effects and risks
- Benefits to using nitrous oxide during labor
- How to use nitrous oxide effectively
- Can nitrous oxide be used with other pain medications?
What is nitrous oxide?
Maybe you’ve used laughing gas at the dentist - that gas you inhale continuously through a nose mask that makes you feel relaxed. It may even help you slip into a drowsy state, or fall asleep entirely. If you choose to use nitrous oxide, also known as laughing gas, during labor to ease the pain of contractions, you will find that it is a very different experience from the one in the dental chair.
Nitrous oxide is a tasteless and odorless gas that can be inhaled for pain relief. Its use during labor is relatively new in the United States, but its first recorded use during childbirth was way back in 1881. Starting in the 1930s, it has been regularly used in other countries around the world, including Australia, Canada, Finland, Sweden, and the United Kingdom. In those countries, as many as 8 in 10 people use nitrous oxide during labor. It has a long and established record of safety and effectiveness, and has the fewest side effects of any of the pharmacological pain relief options available for labor.
When used for pain relief in labor, the gas given is a mixture of 50% oxygen and 50% nitrous oxide (N2O). This is a lower dose than what is given in dental procedures (dentist may use up to a 70% concentration), thus when used in labor it is unlikely to make you lose consciousness. And while nitrous oxide given at the dentist is inhaled continuously, it is only used intermittently during the birth process, further ensuring that you stay awake.
The gas is fully self-administered and only used during a contraction. The mask used for administration is equipped with a negative pressure demand valve that opens to release the gas when you firmly press the mask over your nose and mouth and inhale. The valve closes when inhalation stops. This prevents the gas from leaking out into the room. Additionally, the nitrous oxide delivery devices have a built-in system to remove any trace amounts of escaped gas from the room air, ensuring that hospital staff and your partner are not at risk for exposure.
It is very important that only the laboring person hold the face mask in place. Your partner or doula can’t do it for you. Self-administration allows for protection against excessive drowsiness. If the gas begins to make you feel overly sleepy, the hand holding the face mask will slip down and you will stop inhaling the gas, naturally self-regulating your intake.
How does nitrous oxide work?
Nitrous oxide is a form of analgesia. Analgesics are a category of pain medication that work systemically (throughout the whole body) to alter the perception of pain. They do not remove pain, but help dull pain and make you care less about it. Opioids such as fentanyl, which is also commonly used during labor, are also in the category of analgesics.
According to the position statement on the use of nitrous oxide in labor from the American College of Nurse Midwives, “Nitrous oxide works by increasing the release of endogenous opioid polypeptide compounds (endorphins), corticotropins, and dopamine that are produced in the mother’s brain.”
Endorphins are hormones which help you feel calm, happy, and relaxed. Dopamine is a neurotransmitter that modulates pain perception. Corticotropins are peptides that mediate the effects of stress on the body. These chemicals work well together to take the edge off of pain, reduce anxiety, lessen tension, and create a sensation of well-being.
Perception of pain is more acute with feelings of being scared, tense, or anxious, so the calming effect of nitrous oxide contributes to its pain reducing results. While laughing gas won’t actually make you laugh through your contractions, it may help you cope with the contractions more easily by encouraging relaxation and lessening your perception of contraction sensations.
Side effects and risks
For the laboring person, nitrous oxide may cause nausea, vomiting, drowsiness, dizziness, and hazy memory.
It is very common to experience nausea and vomiting during labor, even without the use of pain medications. If you are already feeling nauseous you can request an antiemetic medication (such as zofran) to be administered before you start to use nitrous oxide to counteract any additional nausea the gas may cause.
If you experience any negative side effects from nitrous oxide, simply stop inhaling the gas. It will clear your system quickly (in about three minutes) and the side effects will subside.
There are no known side effects of nitrous oxide on the fetus. Plentiful research has proven that use of nitrous oxide has no effect on fetal heart rate during labor, nor on newborn respiration or APGAR scores after birth. Nitrous oxide is metabolized in the lungs, but some does enter the bloodstream and can cross the placenta. This is not a concern though, because the gas is quickly cleared from both the maternal and fetal circulatory systems through the maternal lungs when the gas is not being actively inhaled.
Benefits to using nitrous oxide during labor
Nitrous oxide can be used to take the edge off of your pain during contractions, while also encouraging rest and relaxation. It is minimally invasive, and can be used in different birth settings, including in hospitals, in birth centers, at some home births, and sometimes even while in a birthing tub.
Two other forms of medical pain relief commonly available during labor, opioids (another analgesic) and epidural anesthesia both have more potential side effects. In addition to fewer side effects, self-reported studies have found that nitrous may offer more effective pain relief than systemic opioids when used in labor.
Epidurals belong to a different class of pain medication than nitrous oxide or opioids. They are a local anesthetic, which means they provide pain relief by numbing a specific area of the body. They have the ability not only to take the edge off of pain, like analgesics do, but also to stop pain sensations. Anesthetics are much more potent than analgesics, and also have more potential side effects.
One big drawback to using an epidural is its invasiveness and the restrictions it puts on your ability to move and eat. With an epidural in place, your legs will be significantly numbed, and you will be confined to the bed. Depending on your hospital's policy, you will not be able to eat (and sometimes not drink) with an epidural in place. Because epidural anesthesia may affect your contraction patterns and your baby’s heart rate, you will also need continuous monitoring, which may further limit your movements.
With nitrous oxide, you are free to move around as you wish. It can be used while standing, sitting on a birth ball or a rocking chair, or squatting. You might find that you feel a bit unsteady on your feet while inhaling the gas (remember, dizziness is a side effect), so you may wish to sit or stand in one place during a contraction, but when the contraction has ended and you stop inhaling the gas you are able to walk around and change positions as desired. Nitrous oxide use usually does not necessitate any additional monitoring of your contractions or the baby’s heart rate, but policies may vary from one birth place to another.
Occasionally, epidurals can slow the course of labor, but nitrous oxide has not been shown to affect the progress of labor in any negative way. There is also no increased risk of a cesarean birth from using the gas.
It is never too late to use nitrous. Unlike both epidurals and opioids, there are no time limits or timing restrictions. It can be used at any stage of labor, including during the pushing phase, and can also be used in the immediate postpartum period to help relieve pain if you need stitches in your perineum.
Nitrous oxide is the only pain medicine that can be self-administered - if being in control of your pain relief contributes to a sense of empowerment, this can lead to a more satisfying birth experience.
For a first-hand account of what it feels like to use nitrous oxide during labor and how helpful it can be, check out this birth story.
How to use nitrous effectively
Now that you’re sold on the benefits of nitrous oxide, let’s talk about how to use it most effectively when you are in labor.
While the majority of people who opt for nitrous oxide pain relief find it helpful, there is a learning curve involved. It may take you three or four contractions to get the hang of it, so don’t give up too soon! Your labor nurse or doula can help show you the ropes to get the most pain relief from the gas.
It’s important to remember that the more nitrous oxide you take into your lungs, the stronger its pain relieving effects will be. You want to start inhaling the gas about 30 seconds before a contraction starts. If your contractions are coming regularly, your support team can help you keep track of when it is time to apply the face mask. If your contractions are less regular, you can start using the gas at the first sign that a contraction is building.
Hold the mask to your face with firm pressure. You want to create a tight seal between your skin and the mask. Then breathe slowly and deeply, concentrating on your breath. You might find it is helpful to count, aiming for an inhalation that lasts for a slow count of 5. Your partner can encourage you to take deep, long breaths by breathing slowly along with you or counting out loud to set the pace.
The gas itself is odorless, but the mask will be new and may have a "plastic smell" that some find unpleasant. If you are bothered by the smell try closing your eyes and imagining you are at the beach blowing up a large rainbow colored beach ball. That will provide a more pleasant context for the smell from the mask.
If at any point you start to feel too dizzy or sleepy, take a break from using the gas and inhale a few deep breaths of normal room air.
After your contraction ends, you will stop inhaling the gas and feel it quickly leave your system. You’re free to walk around and change positions as much as you want between contractions, but will probably prefer to stay in one place while inhaling the gas. Sometimes in hospital settings the oxygen used to mix with the nitrous oxide is connected to the wall and that means the delivery system is not portable. Other systems can be carted around the room as you find comfortable positions.
Can nitrous oxide be used with other pain medications?
Yes! Choosing to try nitrous oxide for pain relief does not exclude you from moving on to other stronger forms of pain medication.
Nitrous oxide is great for taking the edge off of labor pain, particularly at the peak of contractions, and for some people that is all the relief they need. But others may find they want stronger intervention, especially as their labor grows in intensity. In a study from Journal of Midwifery & Women's Health 31% found nitrous alone provided enough pain relief to see them through labor, while 69% went on to request another pain relief method (epidural or opioids).
Starting off with nitrous oxide before graduating to other medicines with more potential side effects can afford more options for how you cope with labor. Maintaining your mobility and upright posture for as long as possible can allow the baby to move lower into the pelvis and find the most optimal position.
You can also try using nitrous oxide to provide you with some pain relief while you wait for the anesthesiologist to place your epidural. Depending on how busy the hospital is, sometimes there is a delay between when you request an epidural and when an anesthesiologist is available to complete the procedure.
Nitrous oxide is an increasingly popular choice for pain relief during labor in the United States. Ask your doctor or midwife if it is available at your chosen birth setting, and consider making it your first option for pain medication in your birth plan.
Lowdermilk, D. L. (2012). Chapter 17 Pain Management. In Maternity & Women's Health Care
ACNM Position Statement: Nitrous Oxide for Labor and Birth Analgesia
Nitrous Oxide for Labor Analgesia: Expanding Analgesic Options for Women in the United States
Top Ten Misconceptions About the Use of Nitrous Oxide in Labor
Nitrous Oxide As Labor Analgesia
Nitrous Oxide for Pain Relief in Labor