Scottish physician James Y. Simpson is credited with developing the use of anesthesia in childbirth. It's true that Simpson popularized the use of chloroform for childbirth, which he first used in 1847. Earlier that year, he'd used ether in a difficult delivery. But even before that, Dr. Crawford W. Long was using ether as an anesthetic. In fact, it was on this date in history, December 27, 1845, that Long gave his wife ether to help her through the birth of their second child.
When Long did this, he had already used ether on a friend, writes anesthesiologist Almiro dos Reis Júnior, to remove infected cysts from his neck. Long had experience with the substance from so-called “ether parties” where young people would knock each other out for fun. However, the public was skeptical of knocking people unconscious during surgery, so Long stopped using ether in his clinic. “But Long still believed in the importance of anesthesia and administered ether to his wife during the birth of his second child in 1845 and other subsequent deliveries, thus undoubtedly becoming the pioneer of obstetric analgesia,” writes dos Reis Júnior.
Both ether and chloroform had been used recreationally, and both are dangerous if the amount isn't just right. But the relief from the pain of childbirth caught on rapidly, especially after Queen Victoria gave birth using anesthesia. Read about the early days of anesthesia at Smithsonian.