Nitrous oxide, often recognized as “laughing gas,” is increasingly offered as a pain relief option in hospitals and freestanding birth centers. This inhaled gas provides an alternative to systemic pain medications or regional anesthesia, such as an epidural. Expectant parents are primarily concerned with the safety profile of nitrous oxide for both the birthing person and the newborn. Current evidence suggests that when used correctly, it is a low-risk option for managing labor discomfort.
Understanding Nitrous Oxide for Labor Pain
Nitrous oxide (N2O) is administered as a fixed blend of 50% nitrous oxide and 50% oxygen, which is mandatory for medical use in the labor setting. This specific concentration prevents oxygen deprivation and is far less potent than the higher concentrations used for general anesthesia. The gas is a mild analgesic and anxiolytic agent, working primarily to reduce anxiety and alter the perception of pain rather than eliminating it entirely.
Its mechanism of action involves targeting the central nervous system, where it is thought to activate the body’s natural opioid and noradrenergic systems. This process modulates pain signals traveling to the spinal cord, helping the person cope with the intensity of contractions. The effect is not complete pain relief, but a sense of diminished pain and increased ability to manage the discomfort.
Maternal Safety and Side Effects
Nitrous oxide is considered safe for the birthing person because of its rapid onset and clearance from the body. It is administered via inhalation and is quickly exhaled through the lungs; the effects dissipate within five minutes of discontinuing the gas. This rapid clearance profile is an advantage over systemic opioids, which can remain in the bloodstream for a longer duration.
The most common side effects are generally mild and transient, including dizziness, lightheadedness, and nausea, which may occur in up to 13% of users. Some individuals also report drowsiness or a reduced sense of awareness, which is expected given the gas’s anxiolytic properties. Because the effects are short-lived, taking a few deep breaths of room air typically resolves these sensations almost immediately.
Serious maternal complications are extremely rare with the 50% blend, and continuous monitoring is not typically required solely for its use. The self-administration protocol allows the birthing person to control the dosage and stop inhalation instantly if they feel too drowsy or disoriented. Combining nitrous oxide with other sedating agents, such as systemic opioids, is not recommended due to a potential risk of respiratory depression.
Impact on the Fetus and Newborn
A concern is the effect of nitrous oxide on the baby, particularly because the gas is known to cross the placenta. However, its low solubility and rapid clearance protect the fetus and newborn. The gas does not accumulate in the fetal tissues and is quickly eliminated through the baby’s lungs once they begin breathing after birth.
Clinical studies tracking neonatal outcomes, such as Apgar scores, have consistently shown no difference between infants whose mothers used nitrous oxide and those who did not use any pain medication. Apgar scores, which assess a newborn’s well-being at one and five minutes after birth, remain high; one study found scores of 7 or greater in nearly 98% of exposed newborns. Furthermore, the use of nitrous oxide does not negatively affect the initiation of breastfeeding or the baby’s early alertness.
Administration and Efficacy
Nitrous oxide is patient-controlled and self-administered, typically through a mask or mouthpiece held by the birthing person. The correct protocol involves beginning to inhale the gas approximately 30 seconds before a contraction is expected to peak. This timing allows the gas to reach its maximum effect concurrently with the peak of the contraction, providing the most benefit.
The efficacy of nitrous oxide provides analgesia—a reduction in pain—rather than anesthesia, which is a complete loss of sensation. While less potent than an epidural, this level of relief is often desired because it allows the patient to remain mobile, fully aware, and in control of the pain management process.