One common theme could be the challenges Steve Rogers faces while dealing with the pregnancy, considering his role as a superhero. Another might be the relationship dynamics between him and the other characters during this time.
I'm not sure about specific 'pregnant Steve Rogers fanfiction' titles. But you can try searching on fanfiction websites like Archive of Our Own. There might be a wide range of stories there.
Love and family are big themes too. The stories often show how the love between Steve and the OC grows deeper during the pregnancy. And they start to build a family unit, which might be different from a normal family because of Steve's status. It shows how they create their own version of a loving family in the face of all the challenges that come with the situation.
There are quite a few out there. Some focus on alternate universes where Steve Rogers experiences this rather unique situation. You can try searching on popular fanfic platforms like Archive of Our Own. Just be sure to check the tags and ratings to find the ones that suit your taste.
One great fanfiction in this category is 'A New Beginning'. It beautifully explores the relationship between Steve Rogers and the original character as she discovers she's pregnant. It delves into their emotions, from Steve's initial shock to his growing excitement and protectiveness. The story also shows how the OC copes with the changes in her life, both physically and emotionally, while being in a relationship with a superhero like Steve.
The uniqueness lies in the fact that it's a complete departure from the traditional portrayal of Steve Rogers. It challenges the norm and allows for a whole new set of character developments and storylines.
One popular storyline could be them dealing with the challenges of pregnancy during a time of war or superhero duties. Maybe Steve is worried about protecting Peggy and their unborn child from his enemies.
His relationship with Tony Stark might change significantly. Stark could initially be skeptical or even make jokes, but then grow to be more understanding and protective. With Natasha Romanoff, she might be more empathetic and offer practical advice. His friendship with Sam Wilson could become even stronger as Sam is there to support him through the whole process.
A really interesting storyline could revolve around Steve Rogers' pregnancy in an alternate universe. Maybe in this universe, male pregnancy is more common among enhanced individuals. He could be part of a community of male parents - to - be. His pregnancy might also bring out a more nurturing side of him that we haven't seen before. He could start mentoring other expectant fathers, all while still having to deal with the threats that come with being Captain America.
One interesting plot could be the challenges they face in a world that is not used to male pregnancy. They might have to deal with public reactions, both positive and negative. Another plot could be how they support each other through the physical and emotional changes that come with pregnancy.