The relationship would likely become more intense. They would have to rely on each other more, and their bond would deepen as they are about to become parents. Inuyasha would probably become more protective of Kagome.
There could be a fanfic that delves into their backstories more. For instance, exploring Sango's past as a demon slayer in greater detail. How she overcame her family's tragedies and how that has shaped her. Inuyasha and Kagome could be part of this exploration, learning more about Sango and in turn, Sango learning more about their own complex pasts and how they are dealing with it.
Kagome would probably be shocked at first. Then she would start yelling at Inuyasha, demanding to know why he's doing this. She's not the type to just sit there and take it.
In fanfiction, their relationship develops gradually. They start with a bit of mistrust, especially Inuyasha who is guarded. But as they go on adventures together, they begin to rely on each other more. Kagome's healing powers and her ability to see the good in Inuyasha are key factors.
In fanfiction, Inuyasha and Kagome's romance is often a central and exciting aspect. Many writers explore their relationship by delving into the emotional connection they share. Their love is built on mutual understanding, despite coming from different worlds. Inuyasha's rough exterior is softened by Kagome's kindness, and she in turn is drawn to his fierce loyalty and strength.
One common theme is their relationship development. Writers often focus on how Inuyasha and Kagome overcome their differences and grow closer. Another theme is adventure. Since the original series was full of it, fanfics continue with new quests and battles.
A favorite moment could be when Inuyasha saves Kagome from a dangerous demon in a fanfic. His quick reflexes and determination to protect her show the depth of his feelings. Sango might be there to provide backup, and the way they all work together in that intense moment is really exciting.