One possible theme could be love and commitment. The pregnancy would force them to reevaluate their relationship and show how deeply they care for each other. Another theme might be the impact on Narnia. As Caspian is a prince, there could be political implications of this union and the upcoming child. Also, there could be a theme of sacrifice, like Susan might have to sacrifice some of her own desires or plans for the sake of the baby and Caspian.
I'm not sure if there are specific popular fanfictions with Susan and Prince Caspian being pregnant. It depends on the creativity of the fanfiction writers. Some might find it an interesting concept to explore the implications of such a situation on the Narnia universe, while others might not be interested in this rather unorthodox take on the characters. You may need to dig deep into fanfiction communities to find such stories.
Perhaps a plotline where the pregnancy is unexpected and it throws Susan Caspian's life into chaos. She might have to make difficult decisions regarding her future, her relationships, and her own identity. There could also be a plotline where the father of the baby is in some sort of mystery or danger, adding more drama to the story.
I don't know of any specific Susan and Caspian pregnant fanfiction to recommend. It's a rather specific concept, and while there could be some out there, it may be a bit hard to find. Maybe you could start by looking at the works of well - known fanfiction writers in the Narnia fandom and see if any of them have explored this idea in their stories.
A possible plot is that Susan discovers she is pregnant during a time of unrest in Narnia. Caspian is worried about how to protect her and the unborn child. They decide to go into hiding for a while in a secret part of Narnia. There, they live a simple life, and Caspian learns to be more self - sufficient, like fishing and hunting for food. As the pregnancy progresses, they form a deeper bond. Eventually, they return to the kingdom when things have calmed down, and they are welcomed with open arms as they await the birth of their child.
One possible fanfiction could start with Susan discovering she is pregnant. Caspian is overjoyed but also filled with a sense of responsibility. They start preparing a nursery in the castle, with Caspian bringing in the finest woods and fabrics. Susan spends her days knitting baby clothes, dreaming of their future child. Their friends in Narnia are excited too, and they all gather to offer their support and gifts. As the pregnancy progresses, they face some challenges, like when Susan has a difficult day of morning sickness, but Caspian is always by her side, bringing her soothing herbal teas.
I'm not sure specifically about 'Susan Caspian pregnant' fanfiction. You could try searching on popular fanfiction websites like Archive of Our Own or FanFiction.net. They have a wide range of fan - created stories and you might be able to find something related there.
One idea could be that Susan returns to Narnia during a time of great peril, and she and Prince Caspian have to team up to defeat a new, powerful enemy. They might discover hidden powers within themselves along the way.
The relationship can be developed through shared adventures. For example, they could be on a mission to retrieve a lost magical artifact. During this journey, they rely on each other's skills and start to respect and admire one another more deeply.
One idea could be that Susan returns to Narnia in a time of great need, and she and Prince Caspian have to work together to defeat a new, powerful enemy. Maybe they discover an ancient magic that only they can unlock through their combined efforts.