There could be a theme of isolation. Harry running away while pregnant might lead to him feeling isolated from his friends and the wizarding world he once knew. It could also explore themes of love and relationships. For example, how his relationship with the baby's other parent might change or develop during this time. Additionally, it might touch on themes of survival, as he would need to figure out how to support himself and the unborn child.
One possible theme could be self - discovery. Harry, being in such a difficult situation, might go on a journey to find out more about himself and what he truly wants. Another theme could be facing consequences. Running away while pregnant has its own set of challenges and consequences that he would have to deal with.
One possible theme could be self - discovery. Ginny running away pregnant might force her to figure out who she is on her own, away from the expectations of others.
A possible plot is that Hermione runs away pregnant because she has been wrongly accused of something related to her pregnancy. Maybe she was framed for using dark magic to conceive or something similar. So, she runs away to prove her innocence while also protecting her unborn child. Along the way, she might have to use her intelligence and magical skills to evade those who are after her and find evidence to clear her name.
Perhaps it's an enemy character who she had an unexpected encounter with, and this led to the pregnancy. It would add a lot of drama to the fanfiction as she then has to deal with not only the pregnancy but also the implications of the father being an enemy.
She may be running away to protect the baby. Maybe she fears that someone or something in her current environment poses a threat to the unborn child. It could also be that she wants to start anew, away from all the complications and expectations in her present life, so she decides to run away with the hope of building a better future for herself and her baby.
One popular one might be 'A New Beginning' where the story delves into how fem Harry copes with being pregnant and on the run. It focuses a lot on her internal struggles and the challenges of finding a safe place.
I'm not sure of specific 'harry runs away pregnant fanfiction' stories off the top of my head. You could try searching on popular fanfiction websites like Archive of Our Own. They have a vast collection of fanfics, and you can use those keywords in the search bar to find relevant stories.
The Weasley family could also be of great help. Molly Weasley, in particular, has a motherly instinct. She could take Harry in and help him with the pregnancy as if he were one of her own children. The Weasley twins might also be able to create some useful magical items for Harry to use during his time away, like special potions for a healthy pregnancy or charms to keep him hidden. And Ron, as Harry's best friend, would be there to support him emotionally and physically, even if he was initially shocked by the situation.
Maybe Harry feels a sense of guilt. In the context of the war, he might think that he's failed in some way by getting into this unexpected situation. He could believe that his new condition might put others at risk or that he's no longer the hero everyone expects him to be. So, to protect others or to avoid the shame, he decides to run away.
It could be that Naruto discovers something about the nature of his pregnancy that scares him. For example, he might find out that the child has some sort of special power that could put it in danger. So he runs away to figure out how to handle the situation without endangering the village or the child. He might seek out a hermit or an old sage to get advice on what to do.
One possibility could be that Stiles runs away because he's afraid of the reactions from his friends and family. Maybe he thinks they'll be disappointed or angry. He might go to a place where no one knows him to start a new life for himself and his unborn child.