nitrous oxide, better known as laughing gas. an option that had fallen out of favor until now. shawna gave birth to three children at this hospital. and like so many women say using an open do you recall epidural with her left her feeling too much. >> i wasn't able to know when i was having a contraction. i didn't know when i should push. i didn't know when i should breath. >> reporter: so for her second child, she chose a painful natural birth. so by the third, she chose nitrous oxide. >> i would distance myself from the pain but know it was there. >> reporter: the doctor says that's the idea. >> it takes the edge off and there's a little bit of an eye i don't care factor. so a woman very anxious, it decreases her anxiety. >> reporter: nitrous oxide is gaping popularity among midwives especially. as a handful of hospitals are bringing back the gas as an option. but some doctors argue the