Another storyline might involve Harry having to hide his condition from Voldemort and his Death Eaters, as being in a vulnerable pregnant state makes him an even bigger target. He could also form unexpected alliances with female characters who help him through this difficult time.
A plotline might also involve Harry's relationships changing. As a girl, his/her romantic relationships could take a different turn. The pregnancy could add an extra layer of complexity. For example, if there was a previous romantic interest in a female character, that dynamic could shift completely. Also, there could be a sub - plot about how the wizarding society views a pregnant, transformed Harry, and the challenges he/she faces in a world that has certain expectations and norms.
One possible storyline could be that Harry is cursed by a dark wizard. The curse has the unexpected side - effect of making him pregnant. He then has to search for a way to break the curse while dealing with the physical and emotional turmoil of pregnancy. Another could be that it's a result of some experimental magic gone wrong. He might have been trying to help someone with a fertility spell and it backfired on him.
One possible storyline could be that as Spiderman turns into a girl, he - or rather she - has to deal with the sudden change in how society views her. She might face different challenges in her superhero duties, like people not taking her as seriously at first. Another could be that she discovers new powers or abilities that are unique to her female form.
One possible storyline could be that Sirius initially panics when he finds out about the pregnancy. He might struggle with his responsibilities as he has a rather wild and carefree nature in the original story context. He could then gradually grow into the role of a father - to - be, facing challenges from his friends and family who may have different expectations.
I'm not sure specifically which 'pregnant Harry turned girl' fanfictions are out there. You could try searching on fanfiction - specific websites like Archive of Our Own. They have a vast collection of fan - created works and you might be able to find something related to this rather unique concept.
One possible storyline could be the challenges they face in preparing for the baby. For example, they might struggle with finding a suitable place to live as a family. Another could be how their families react. Harry's wizarding friends might be very excited and offer all kinds of magical help, while Padma's family in the wizarding world could have different cultural expectations.
One possible storyline could be that she has to hide her pregnancy from her enemies who would use it against her. Another could be that she discovers new magical powers related to her pregnancy.
One possible storyline could be about Renamon facing the challenges of pregnancy in a world full of adventures. Maybe she has to balance her pregnancy with her duties or training. Another could be the reactions of her friends and allies to her being pregnant, whether it's shock, excitement or concern.
One possible storyline could be that Hiccup and Astrid are happily married and the pregnancy is a planned and joyous event. They start preparing for the baby's arrival, like building a nursery and getting baby supplies. Another could be that the pregnancy is unexpected, causing some initial shock but then they gradually embrace the idea and look forward to becoming parents.
Well, perhaps a storyline could revolve around Borusara preparing for the arrival of the baby. They might be shopping for baby clothes, setting up the nursery, and discussing names for the little one. It could also show how their relationship evolves during this special time.