Questions about the Tower of London?

I'm writing a book that I was hoping could take place in Victorian England, if not then a little bit soon, but I'm stuck. I was going to have my main character's mother be trapped in the Tower of London when she gives birth, but as far as I have researched the Tower of London was used mostly in the 14th and 15th century. So I was wondering what is the latest year the Tower used as a prison, and what are some famous prisons used anywhere from the late 1700s to the mid 1800s. Thanks so much :)