Maybe it's to create more tension and emotional depth in the fanfiction. Pregnancy often brings a lot of changes and challenges that can drive the plot forward.
Sure is. It's a fictional story with created characters and plotlines. The events and situations presented in it are not based on real-life events but are the product of the author's imagination.
Well, sometimes in fanfiction, writers take liberties to create unexpected plotlines. Maybe this pregnancy was a way to bring a fresh perspective or add more layers to the story of Hannah and Bryce.
In 13 Reasons Why fanfiction, Hannah could be depicted with a stronger determination to overcome her past or might have new relationships that shape her differently. Also, her character development could take unexpected turns.