One possible storyline could be how they deal with the challenges of impending parenthood while still being involved in the galactic struggle. For example, they might have to find a safe place to raise their child away from the Empire's reach.
The pregnancy could be a false alarm. It might be a ploy by the Empire to discredit Leia and Han. They spread the news of the pregnancy to make the Rebellion look bad or to create chaos within their ranks. So, Leia and Han would have to prove that it's not true and also find out who's behind this scheme.
Hans Solo's origin story is quite interesting. He was born on Corellia. He had a rough childhood and got involved in various adventures from a young age. He became a smuggler and was known for his piloting skills, especially flying the Millennium Falcon. He got into all sorts of scrapes with different alien species and shady characters in the galaxy.
The pregnancy might change the way other characters interact with them. Allies could be more protective, while enemies might see it as a new vulnerability to exploit. For example, the Empire could try to use the pregnancy as a way to blackmail or manipulate them. It also gives fanfiction writers a chance to explore different aspects of the characters' personalities as they adapt to this new situation.
If Leia and Han had a child, it would change the power dynamics in the Star Wars universe. Their child could potentially be a very powerful force user, which would either be a great asset to the Rebellion or a huge target for the Empire. This could lead to new alliances being formed as different factions try to either protect or use the unborn child for their own purposes.
Princess Leia found herself in a magical forest in a far - flung part of the galaxy. The trees were made of a shimmering blue - green substance and glowed softly at night. She was searching for a lost Jedi artifact that was crucial for the resistance. As she explored, she encountered a group of tiny, winged beings. They were initially wary of her but soon realized she was there to help. They showed her the way to a hidden cave where the artifact was hidden. However, a dark sorcerer had placed a curse on the cave. Leia had to use her wits and her connection to the Force to break the curse and retrieve the artifact.