There could be. The Pokemon fandom is quite large and diverse. Fanfic writers love to create unique storylines for their favorite characters. Ash and Serena are popular characters, so it's not surprising that someone might write a fanfic about them having a family. But these types of fanfics may not be endorsed by the official Pokemon creators.
Overcoming obstacles. There could be various obstacles like financial concerns (in the context of the Pokémon world), or dealing with enemies who might see the baby as a threat. The fanfic may show how Ash and Serena work together to overcome these challenges and ensure a safe and happy future for their family.
In fanfiction, anything can happen. However, without specific details of the particular fanfic, it's hard to say for sure if Serena is pregnant. Some fanfictions might explore this plotline for the sake of drama or character development. It could add an interesting twist to the relationship between Ash, Serena and Lemon, but it also depends on the overall theme and direction the author wants to take the story.
One possible storyline could be that Ash and Serena have been traveling together for a long time and their relationship deepens. They might face some initial shock and then start to plan for their future together. They could have to deal with reactions from their friends and family, like Pikachu being both excited and a bit confused.
Another theme could be the reactions of their friends and family. In these fanfics, characters like Ash's Pokémon partners or Serena's mother might have different reactions to the news. It adds drama and more storylines. For example, some friends might be overjoyed while others could be worried or surprised. Also, there might be a theme of self - discovery for both Ash and Serena as they enter this new phase of life, learning more about themselves and each other in the process.
One great Ash and Serena fanfic is 'A Journey Together'. It beautifully captures their relationship growth as they travel through the Pokémon world. The author does an amazing job of showing Serena's determination to support Ash in his Pokémon battles and how Ash starts to see Serena in a different light.
In the fanfic, the reaction in the Pokemon world would be mixed. The local Pokemon townspeople might hold different views. Some would see it as a beautiful thing, a new start for Ash and Serena. Others might worry about how it will impact their Pokemon training. The Pokemon gym leaders could also have different reactions. Some might offer their gyms as a safe place for Serena to stay during her pregnancy, while others might be more hesitant, fearing it could set a precedent that might disrupt the normal flow of the Pokemon training world.
You can try searching on popular fanfic platforms like Fanfiction.net or Archive of Our Own (AO3). These platforms have a wide variety of fanfics, and you might be able to find Ash x Serena pregnant fanfics there. Just use the search function and type in relevant keywords.
Perhaps the story could involve a mystery related to Serena's pregnancy. There could be some strange events or prophecies in the Pokémon world that seem to be connected to the baby. Ash and Serena then have to go on a journey to figure out what it all means. Along the way, they meet new Pokémon and characters who either help or hinder their search for the truth.
One possible plot development could be that Ash and Serena have to deal with the new responsibilities of having a baby. This might cause some tension between them as they figure out how to balance their own goals and the needs of the family. Lemon could be involved as a support system, or perhaps as a source of conflict if there are romantic feelings involved among the three. For example, if Lemon has feelings for Ash, Serena's pregnancy could make those feelings more complicated.