Another storyline could involve a mystery or a threat during her pregnancy. Maybe there are dark forces that are after the unborn baby for some reason. Princess Cadence then has to protect herself and her unborn child while still fulfilling her royal duties. This could lead to some exciting adventures and heroic moments.
One possible storyline could be Princess Cadence preparing for the arrival of her baby. She might be seen redecorating the nursery, choosing baby names, and sharing her pregnancy experiences with her friends and family. For example, she could have heart - to - heart talks with Twilight Sparkle about the joys and fears of motherhood.
One possible storyline could be that Princess Celestia discovers she's pregnant and has to deal with the political implications within her kingdom. Her pregnancy might cause a stir among the nobles and commoners alike, as they wonder about the future of the realm with an heir on the way.
Shining Armor, her husband, would surely be a main character. He could be shown as a very supportive and protective partner. He might be by her side during doctor visits, making sure she is comfortable and taking care of all her needs.
One possible storyline could be about Gwen facing the challenges of being a superhero while pregnant. She might have to deal with villains who try to take advantage of her condition. Another could be her preparing for the arrival of the baby, like setting up a nursery with her friends and family's help. And also, there could be a story where she discovers new powers related to her pregnancy that help her protect herself and the unborn child.
One possible plotline could be that Naruto is somehow transported to the world where Princess Cadence is from. Maybe he has to help her protect her kingdom from an unknown threat. He could use his ninja skills like shadow clones to confuse the enemies.
One possible storyline could be that they accidentally get caught in a situation where a magic spell makes Nami pregnant. Zoro then has to quickly come to terms with becoming a father and they embark on a journey to find a way to reverse it, but during this time, they start to bond in a new way over the unborn child.
In a fanfic, Tsunade's pregnancy might be a result of some sort of experimental medical jutsu gone wrong. Naruto could be the one to find a way to reverse it if she doesn't want the baby, or he could help her through the difficult pregnancy. He could also help protect her from those who might see her pregnancy as a weakness to exploit in the village.
One possible storyline could be that they face threats to their unborn child. For example, an old enemy of Aquaman might try to use the pregnancy as a way to get to him. They could also have a journey to find a safe place for Mera to give birth, perhaps a hidden underwater realm that has special powers to protect the baby.
One possible storyline could be about Clary facing the reactions of her family and friends. They might initially be shocked but then come around to support her. Another could be her struggle to continue her education while dealing with the pregnancy.
One possible storyline could be that Leon and Ada find out about the pregnancy unexpectedly. They then have to deal with the challenges of their dangerous line of work while also preparing for a new life. For example, Leon might be extra protective of Ada during their missions.
One possible storyline could be about the challenges she faces during her pregnancy. For example, how she deals with the physical changes and the reactions of those around her in her fictional world.