The first reference I linked specifically controlled not just for disorders that could lead to similar symptoms, but even things like the mother's socioeconomic

The first reference I linked specifically controlled not just for disorders that could lead to similar symptoms, but even things like the mother's socioeconomic status, etc. The effect was still huge. I don't think anyone's seriously suggesting simply forgoing anesthesia in life threatening cases, but people might want to rethink a routine tonsillectomy or some dental work.