One idea could be exploring how Marinette balances her superhero duties with her pregnancy. Maybe she has to be more cautious during battles, and her partner Chat Noir has to be extra protective. Another plot could involve her friends and family finding out. Some might be overjoyed while others could be worried about how she'll handle it all.
Well, a great plot could be that Marinette discovers she's pregnant right before a major akuma attack. She has to quickly figure out how to keep herself and the baby safe while still trying to defeat the akuma. Also, the father's identity could be a mystery at first, leading to a lot of speculation among the characters in the fanfic. This would add an element of mystery and drama to the story.
A possible plot idea for a Marinette pregnant fanfic in Miraculous Ladybug could be centered around her pregnancy cravings. These cravings could lead her to some unexpected places or situations. For example, she might be drawn to a particular bakery where an akuma victim is located. This would create a unique situation where she has to deal with both her pregnancy needs and her superhero responsibilities at the same time. It could also be interesting to see how her relationship with Tikki changes during this time, as Tikki might have to offer different kinds of support.
One interesting plot could be Felix discovers Marinette's secret identity as Ladybug by accident. He then has to decide whether to use this information for his own gain or keep it a secret. Maybe he starts to develop feelings for her because of her dual identity and the strength she shows as Ladybug.
She could be turned into a mouse - like creature by an experimental akuma attack. As a mouse, she discovers new parts of Paris that are usually hidden from humans. This could include secret underground tunnels or the rooftops in a whole new perspective. She might also meet other kwamis who are more active in these hidden areas.
One plot idea could be that Marinette and Felix are paired up for a school project. Felix, initially cold, starts to see Marinette's kindness and creativity, and they develop an unexpected friendship. This could lead to some comical moments as Marinette tries to hide her Ladybug identity from him while Felix is being his usual perceptive self.
One plot idea could be Marinette having to deal with the pressures of being a princess while also being Ladybug. For example, she might have to attend royal balls and diplomatic events in her princess role, all while secretly protecting Paris as Ladybug. Another idea is that an evil villain targets her specifically because of her dual identity, trying to take over both the kingdom and Paris. Maybe there could also be a plot where she has to choose between her duties as a princess and her responsibilities as Ladybug, creating an internal conflict.
One interesting plot could be that Marinette - as - Kwami is accidentally discovered by Hawk Moth. He tries to capture her to use her powers for his evil plans. Marinette then has to use her wits and any new Kwami - like abilities she has to escape and warn Ladybug (who she can't transform into at the moment). This would create a lot of tension and action in the fanfiction. Also, it could explore how Marinette feels being in such a vulnerable state.
One idea could be that Marinette discovers she's pregnant during a lull in the fight against Hawkmoth. This adds a whole new layer of complexity as she has to balance her superhero duties with her pregnancy. She might have to keep it a secret from Chat Noir at first to avoid him being overly protective and getting distracted from their mission.
One idea could be that Marinette vomits due to extreme stress. Maybe she's facing too many akuma attacks in a short time and the pressure gets to her physically. Another could be related to a strange side - effect of using the Ladybug Miraculous. For example, if she overuses her powers in a short period, it might cause some sort of physical reaction like vomiting.
A possible plot idea is that Marinette is akumatized after being wrongly accused of something at school. Her akumatized form could have the power to manipulate people's memories, making them believe false things about their friends. This would cause a lot of chaos and mistrust in Paris. Chat Noir would have to find a way to reach the real Marinette inside the akumatized shell and convince her to break free. It would be a story full of drama and action.
A really interesting fanfiction idea could be that Lila and Marinette switch personalities for a day. This would be a comical yet thought - provoking situation. Lila would have to deal with Marinette's responsibilities and kindness, while Marinette might struggle with Lila's devious ways. It could lead to both of them having a new perspective on each other.
Another plot could involve the villains finding out about Ladybug's pregnancy and trying to use it to their advantage. This would create a whole new level of conflict for our heroes.