In A Game of Thrones , the maegi caused Drogo 's wound to fester .
The wound festers and Daenerys commands a captive maegi to use forbidden blood magic to save him ; the treacherous maegi sacrifices Daenerys ' unborn child to power the spell , which reclaims Drogo 's life but leaves him in a vegetative state ; she had caused Drogo 's wound to fester , as well .
A Game of Thrones