According to this post in History Buff Victorian doctors labored under some very peculiar notions, especially when it came to women’s health.
Apparently, “professional” consensus held that reading novels made women “incurably insane”. And it was more than a women’s mental state that was under threat. According to literature scholar Catherine Golden in her book Images of the Woman Reader in Victorian British and American Fiction, “Reading was damned because it was thought to damage a woman’s nervous system and reproductive health. Medical authorities linked excessive, unsupervised reading to a host of female reproductive ailments… insanity, and premature death.”
Fortunately for women readers, not to mention untold authors, publishers and libraries, medical science has come a long way since Victorian England.