Well, in such a fanfiction, the pregnancy might be a result of an accident. Chitoge could be worried about how it will affect her relationship with Raku. Maybe she tries to hide it at first. But as the story progresses, things start to come out. Their friends like Kosaki might have different reactions, adding more drama to the plot.
One common theme is the idea of unexpected change. The pregnancy is an unplanned event that shakes up the characters' lives. Another theme could be love and support. Raku and Chitoge might have to show their love for each other in new ways as they face this big change. Family also often plays a role, with their families having different reactions to the pregnancy.
Another plot could involve a time - travel aspect. Raku and Chitoge could be sent back to a time when their families first had the feud. They could try to prevent the feud from starting, which would change the course of their relationship in the present. This would give them a chance to get to know each other without the burden of the arranged marriage plot.
For Raku, he could be developed further by exploring his insecurities more deeply. In the original story, he's often caught up in the love polygon, but we could see him face his own self - doubt about whether he's worthy of Chitoge's love. This could make his character more relatable.
One possible plot could be that it's an alternate universe where Naruto and Tenten end up together in a situation that leads to pregnancy. Maybe they were on a mission together and some strange magic or jutsu affected them, causing Tenten to become pregnant. They then have to deal with the reactions of their friends and the challenges of impending parenthood.
The plot could be that Naruto and Mei are in a secret relationship. When Mei gets pregnant, they try to keep it a secret at first. However, as the pregnancy progresses, it becomes harder to hide. Mei starts to show signs of a special chakra within her womb, which makes some villains target her. Naruto has to fight off these villains while also dealing with his own insecurities about becoming a father. They finally decide to reveal their relationship and Mei's pregnancy to their closest friends and allies, who then rally around them to protect them and the unborn child.
One possible plot could be that they initially struggle with the news of the pregnancy. Will might be worried about being a good father, while Kayla could be dealing with the physical and emotional changes. Maybe they face some family or friend reactions that are not entirely positive at first, but through their love and determination, they start preparing for the baby, like looking for a new place to live or buying baby stuff.
One possible plot could be that Chad and Taylor are a young couple who find out they are unexpectedly pregnant. They initially panic as they are not fully prepared for this new stage in life. They could face reactions from their families, some being supportive and others disappointed. As the pregnancy progresses, they start to grow closer and more responsible, learning about parenting and making plans for their future as a family.
One possible plot could be that Ash and Serena decide to start a family after years of adventures together. They face the joys and challenges of pregnancy, like Serena having cravings for Pokémon - themed treats and Ash trying to learn all about how to take care of a pregnant partner. Their Pokémon friends also get involved, with Pikachu helping out in small ways around the house.
One plot idea could be Nejire's journey through pregnancy while still trying to be a hero. She might face challenges like hiding her condition from villains who could target her. Another could be the reactions of her friends and loved ones, like how they support her and deal with the changes in their relationships.
Well, perhaps in the fanfiction, there's a mission where they are the only survivors and during their time of isolation, they develop a deep bond which leads to Sakura getting pregnant. The story could then revolve around how they deal with this new situation, with Kakashi trying to protect Sakura and the unborn child from any potential threats.