There was a woman who boxed in the 1950s while pregnant - Apparently.
In 1955, Lottie "Tiger" Moller, a boxer from Denmark, went on to win 13 of 18 fights while pregnant with her second child. Her boxing career spanned from 1949 to 1956, with a total of 35 wins and 9 losses. Her unique story has been well-documented in boxing history, with many considering her to be one of the pioneers of women's boxing.
This fact is verifiable through various boxing history resources, including the International Boxing Hall of Fame and several Danish boxing archives.