Entonox is a medical gas mixture containing 50% nitrous oxide and 50% oxygen. It is widely used in Nigerian labour wards because it provides safe, rapid pain relief during childbirth without putting the baby to sleep. The nitrous oxide acts on the central nervous system to alter pain perception, while the high oxygen concentration ensures the mother and fetus remain well-oxygenated.
One common misconception is that Entonox completely takes away all labor pain. Midwives must explain to mothers that it simply takes the sharp edge off the contractions, helping them relax and cope better.
Before offering pain relief to a laboring woman, the midwife must inspect the gas delivery system.
Effective administration depends entirely on the correct breathing technique. The midwife must instruct the mother to hold the mouthpiece or mask tightly and take deep, steady breaths of the gas as soon as she feels a contraction beginning.
Because nitrous oxide takes about fifteen to thirty seconds to reach peak effect, starting too late leaves the woman in pain while the contraction peaks. The mother must control the demand valve herself—this is self-administration. If she becomes too drowsy, her hand drops away from the mask, stopping the flow of gas automatically. This built-in safety feature prevents accidental over-sedation.
While using Entonox, the mother requires regular clinical observation to ensure her safety and comfort. Midwives should monitor vital signs, particularly respiratory rate and level of consciousness, because excessive use can cause lightheadedness or drowsiness. Assess her pain coping mechanisms and encourage regular sips of water, as the dry gas can cause a dry mouth. Ensure the delivery room is well-ventilated to prevent ambient nitrous oxide build-up, which can cause dizziness in attending healthcare staff.
Entonox remains popular in maternity units because it is non-invasive, acts quickly, and leaves the body rapidly once inhalation stops. It does not slow down uterine contractions and has no harmful direct effect on the newborn baby, allowing the mother to remain mobile and an active participant in her birth experience.
However, its pain-relieving potency is relatively mild compared to regional analgesia like an epidural. Some women experience lightheadedness, nausea, or a dry mouth, and the required breathing technique can be difficult to maintain when a woman is exhausted or distressed during transition.
Side effects from Entonox are usually short-lived and resolve quickly once inhalation stops. Nausea and vomiting can occur; midwives should have an emesis bowl ready and reassure the patient. Dizziness, dry mouth, and mild tingling sensations in the fingers are also reported.
If a woman feels overly confused or disoriented, encourage her to take a break from the gas, remove the mask, and take slow breaths of room air. Prolonged use over many hours can occasionally interfere with vitamin B12 metabolism, though this is rarely an issue during normal labor durations.