N2O is a nonflammable, tasteless, odorless gas. It was first synthesized by the English scientist and theologian Joseph Priestly in 1772, and was first used as a labor analgesic by Stanislav Klikovich in Poland in 1881. Although much more frequently used in the UK and Canada, interest in nitrous oxide for labor pain management is increasing in the USA. What is its mechanism of action? Is it effective? What are the contraindications? Let’s review this topic...NOW.
