The pain of giving birth has been likened to amputating a finger. While everyone's childbirth experience is subjective of course, it's safe to say it hurts. A lot. And though doctors and midwives can offer everything from birthing balls to epidurals to ease, dull, and numb that pain, one thing that hasn't been in the tool kit in the U.S. for decades is nitrous oxide. This colorless, odorless gas -- the same “laughing gas” often administered at the dentist’s office -- when inhaled causes the woman's body to relax and gives her a calm feeling.