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Sep 8

Nitrous Oxide & Mountain Midwifery Center

General Information

Nitrous Oxide (N2O) (“Nitrous”) is a colorless, nearly odorless, non-flammable gas first synthesized in the 1700’s (4). It was not widely used medically until the mid 1850’s and was introduced as an analgesic for dental procedures (4). It is also frequently used as anesthesia during pediatric surgical procedures due to its quick onset, quick dissipation, and low side effect profile. It is sometimes called “laughing gas” and is widely used throughout the industrialized world. In fact, in many counties, up to 80% of women will use Nitrous at some point during their labor (1). In the United States, Nitrous was widely used for labor, beginning in the 1930’s through the 1970’s, prior to wide spread use of epidural anesthesia (2). Recently, there has been interest in bringing back the use of Nitrous in the United States. Currently, there are several facilities, both hospitals and free standing birth centers, using Nitrous Oxide for pain management in labor.
In labor, Nitrous Oxide is used as an analgesic, not an anesthetic. This is an important distinction and one worth clarifying. Anesthesia is a substance that induces “the loss of feeling in a person’s body or part of the body” (Merriam-Webster online dictionary). An analgesic creates “insensibility to pain without the loss of consciousness” (Merriam-Webster online dictionary). In essence, an anesthetic creates a feeling of numbness usually with loss of consciousness, while an analgesic helps to alleviate the sensation of pain while remaining alert. In this sense, Nitrous Oxide can be a powerful tool helping some women cope with the sensations of labor. In addition to being an analgesic, Nitrous also acts as an anxiolytic, decreasing anxiety and allowing the user to reach a deeper state of relaxation (4). Nitrous is also known to increase the release of endorphins and prolactin while decreasing the release of cortisol, or the “stress hormone” (4). However, Nitrous has no effect on the release or effectiveness of oxytocin so it will not inhibit contractions or labor progress (4). In this way, Nitrous can facilitate relaxation, reduce the perception of pain, and give women a sense of control over her pain management.
A key component of Nitrous use is patient autonomy and control. The laboring woman must be in complete control of the timing and use. Only the laboring woman may hold the mask to her face and it may not be propped up or strapped to her. The effects of nitrous are felt within seconds and then also dissipate within seconds. Due to this level of control, many women report feeling empowered, increasing a sense of confidence after using nitrous. (1,2,3,4). Nitrous does not relieve all sensation, it simply allows the user to relax and work easier through contractions.

Maternal Effects

As stated above, Nitrous has been in widespread use in many countries since the early 1900’s. When Nitrous is used as an analgesic in labor at a ratio of 50% N2O and 50% O2, it has been clearly documented to be a safe option for women (1, 2, 4). Women remain alert, retain motor and sensory function and their uterine activity is not inhibited (2,3). Nitrous can be used in any stage of labor and can be beneficial for certain postpartum procedures such as laceration repair (1,2,3). The most common side effects of nitrous are dizziness, nausea, vertigo, and vomiting and rarely some women may experience anxiety and dysphoria (2,4). If these side effects are significant, the woman simply stops using nitrous and the effects will dissipate within minutes (2,4).

Newborn Effects

In over 100 years of use as analgesia during labor, there have never been any published studies or cases of Nitrous having a negative effect on the newborn (1,2,4). Several studies have clearly demonstrated a lack of negative effects, for example: there are no effects on newborn heart rate during labor or Apgar scores, no increase in rates of meconium stained fluid, no effects on newborn cord blood gases (1,2,4). It has also been demonstrated that when women use Nitrous, no increased need for neonatal resuscitative efforts was found (1).
Breastfeeding is an integral component to care at MMC and is very important to our families as well. The use of Nitrous in labor has been shown to have no negative impact on breastfeeding initiation or long term success (1, 2).

Use at MMC

We are excited to be able to offer this option to our clients and are proud to be the first facility in the state to offer Nitrous for labor. We want to be clear that this is an option: we still believe strongly in comprehensive childbirth education, continuous labor support, freedom of movement in labor, hydrotherapy, and all other forms of labor coping techniques. Nitrous will simply be an additional tool for women who desire its’ use. Nitrous does not inhibit labor progression, is completely controlled by the laboring woman, does not require more invasive monitoring, does not inhibit the ability to remain aware, and does not require the restriction of movement. For these reasons we feel Nitrous use aligns with our overall philosophy of care (1,2,3,4).
With the exception of rare medical conditions, all women who are admitted to MMC in active labor will have the option of Nitrous Oxide. One condition of use is the continuous presence of either a support person or a member of MMC staff. Women will be able to use Nitrous while in the birth pools. There will be small fee for the use of Nitrous covering the cost of the supplies including a single use mask, Nitrous and Oxygen gases, and setup of the equipment. For our clients who have questions about Nitrous, please discuss them with one of our midwives, nurses or educators.


1. ACNM Statement
2. Nitrous Oxide as Labor Analgeia
3. Collins Starr Baysinger Bishop Publication
4. Safety & Risks of Nitrous Oxide
*In order to hyperlink these articles, we have used the links through the Porter website. Porter is the company that we purchased our nitrous unit from. However, the articles are completely independent from Porter and not endorsing any specific company or nitrous unit.