FDAnews
www.fdanews.com/articles/134258-laughing-gas-returning-as-option-for-laboring-moms

Laughing Gas Returning as Option for Laboring Moms

February 14, 2011
Labor pain is nothing to laugh at. Yet. … The use of nitrous oxide, or laughing gas, during childbirth fell out of favor in the United States decades ago, and just two hospitals — one in San Francisco and one in Seattle — still offer it.
Houston Chronicle