Nadia was Katherine's only child. Katherine gave birth to Nadia onscreen, though these were in flashbacks in the episodes Katerina and 500 Years of Solitude. Both turned themselves for specific purposes, Katherine as a way to save herself from being sacrificed by Klaus and Nadia so she can find her mother.

Who is Katherine's baby daddy?

In the season four finale of The Vampire Diaries, Graduation, Katherine slept with Niklaus Mikaelson and conceived her daughter, Adyelya.

How old is Katherine Pierce?

Katherine is seen in the 1800s as she meets Damon and Stefan, and in the 1920s as she watches over Stefan. But by the time of her death in The Vampire Diaries's season 5, as a delayed side effect of taking the cure for vampirism, Katherine is over 500 years old.