I'm not sure specifically as there could be many different interpretations. It might be a fanfiction where the character Kaoru from Ouran does something that causes harm, either physically or emotionally, to another character in the Ouran universe.
I'm not very familiar with this specific fanfiction. However, in general, pregnancy fanfictions often explore new aspects of character relationships. It might delve into how Haruhi and Kyoya handle the unexpected situation, and how it impacts their relationship within the Ouran High School Host Club setting.
One popular theme is the forbidden love between a human and a vampire within the Ouran High School setting. It adds an exciting and dangerous element to the typical school romance. Another theme could be the struggle of vampires to fit into human society while hiding their true nature. This often leads to some interesting character development and plot twists.
Love and romance can also be common themes. Sometimes the male OC falls in love with one of the female characters in Ouran, or there are complex love triangles involving him. Also, the theme of adapting to a new environment is quite prevalent. The male OC has to adjust to the rather extravagant and unique culture of Ouran High School.
Yes, it could be. In some Ouran fanfictions, creative writers might develop a plot where Harry has a best friend who is Honey. Fanfictions often take existing characters and create unique relationships among them.
Friendship is also a big theme. Characters from both series form new friendships. For example, the more reserved characters in Ouran might befriend the quieter Hetalia characters, like Japan from Hetalia might bond with a character like Mori from Ouran over their shared calm demeanor. And they learn from each other, growing as individuals.
One popular 'Ouran Lemon Fanfiction' might be those that explore the romantic relationships between the main characters in a more intense way. For example, stories that focus on the relationship between Haruhi and Tamaki could be quite sought - after. They might add in extra emotional and physical interactions that are not in the original anime or manga.
Fanfiction.net is also a place to check. There are a lot of Ouran High School Host Club fanfictions on there. Just use the search function and type in relevant keywords like 'Haruhi', 'Kyoya', and 'pregnancy'. But be aware that the quality can vary greatly on this site.
There are also 'Ouran Crossover Fanfiction' stories that involve a crossover with 'Black Butler'. In these, the Victorian - era setting of 'Black Butler' clashes and also meshes in a unique way with the modern - day (sort of) setting of Ouran. Ciel might be both intrigued and exasperated by the Host Club's antics.
There could be a story where the relationships between the characters in 'Ouran Highschool' are explored in a more emotional and deep way in the fanfiction. For example, how two characters overcome their differences and form a strong bond. It might show their growth and development in a new light compared to the original story.