Yes, there might be. The 'Vampire Knight' fandom is quite large, and it's possible that some fans have created fanfiction involving Zero being in a situation related to pregnancy. However, not all fanfictions are easy to find, and the content can vary greatly in terms of quality and adherence to the original story's themes.
Well, it could be that they hide the pregnancy at first. They might be afraid of how the others will react. After all, in the Vampire Knight world, their relationship is already complex and this will add another layer of complication.
You can start by looking on popular fanfiction websites such as Archive of Our Own (AO3). It has a large collection of 'Vampire Knight' fanfictions, and you might be able to find one related to Zero and pregnancy by using the search function. Another option could be FanFiction.net, though the search might be a bit more difficult as it has a vast amount of content.
One possible aspect to analyze in Vampire Knight Pureblood Zero Fanfiction is the character of Zero. He is a complex character with his struggle between his vampire side and his human side. Fanfictions often explore this internal conflict further, perhaps by creating new scenarios where he has to make difficult choices. For example, in some fanfictions, he might be faced with the decision to save a human or a vampire, and this would really test his loyalties and his sense of self.
In Vampire Knight fanfiction involving Kaname and Zero, there could be various interpretations. One could be a story where their relationship evolves in a world full of vampire politics. They might have to face challenges together against the traditional vampire hierarchy that disapproves of their bond. This could lead to them growing closer and perhaps having a deeper connection that goes beyond the ordinary friendship or rivalry shown in the original series.
One possible fanfiction could be about Kiryu's backstory in 'Vampire Knight Zero'. Maybe it delves into his early days before coming to the main events of the story, his family life, and what led him to be the person he is in the series.
A fanfiction could explore Kaito's past and how it intersects with Zero's. Maybe Kaito has some secrets that could either help or hinder Zero in his fight against vampires. It could be a story full of mystery and revelations as they dig deeper into their intertwined histories.
One possible aspect of this fanfiction could be the complex relationship between Zero and Ichiru. In the Vampire Knight universe, they have a very strained brotherly bond. In fanfiction, authors might explore how to heal that bond or what could have been different in their relationship if certain events hadn't occurred.
One possibility is that there is a new kind of vampire ability or disease that causes this situation. Zero and Kaname might be the first victims of it. The story could then focus on their journey to find a cure or a way to handle this unexpected situation. They would have to face their own feelings for each other, as well as the reactions of their friends and foes. It would be a complex and emotional story with many twists and turns.
Their relationship would become extremely complex. If Zero were pregnant, they would have to rely on each other more. Kaname, who might have been somewhat aloof before, would likely become more protective. Zero, on the other hand, would have to deal with his own feelings of vulnerability and dependence, which could be a big change from his usually tough - guy image.