Among the spells Hermione has used are Petrify, a full-body binding spell, Forgetfulness, which can alter one's memory, and Exploding Thunder (the Blast Spell), among other spells she may have used in the Harry Potter series. Harry Potter and the Prisoner of Azkaban wasn't enough. Everyone, please click to read the novel!
Hermione had used Petrify All, a spell that bound the whole body, Forgetfulness All, a spell that altered part or all of a person's memory, and though she was not very good at it, she had used Food Charm (a spell for cooking food, not for making it appear). Harry Potter and the Prisoner of Azkaban wasn't enough. Everyone, please click to read the novel!
The spells Hermione had used included Alohomora (Lockpicking Charm), Wingsium Leviosa (Flight Charm), Locomoter Morts (Leg Locking Charm), Petrificus Totalus (Body Binding Charm), and Oblivion (Memory Charm). She could also use simple spells to repair Harry's broken glasses. Harry Potter and the Order of the Phoenix is not enough. Please click to read the novel!
On the train, Hermione had cast the Reparo Charm on Harry to fix his taped glasses. Harry Potter and the Sorcerer's Stone was not enough. Everyone, please click to read the novel!
In the Harry Potter series, the first spell Hermione learned was the Levitation Charm (Wingardium Leviosa). Harry Potter and the Sorcerer's Stone was not enough. Everyone, please click to read the novel!
According to the Harry Potter series, Hermione's more commonly used spells were Thunderbolt Explosion (Blast Spell), Forgetfulness, Shadowless Spell, Levitation Spell, and so on. Hermione had also used spells like Petrify and the Food Charm (although she was not very good at it) in certain situations, but the first few were used more frequently in the story. Harry Potter and the Sorcerer's Stone was not enough. Everyone, please click to read the novel!
In the Harry Potter novel, author J. K. Rowling confirmed that Hermione had indeed fulfilled her original plan and that the Granger family had a joyous reunion, which meant that Hermione had cast a curse on her parents to restore them. However, in the movie version, the way Hermione used the Memory Charm was heard by the audience, and this specific spell was irreversible, which was different from the plot in the novel. Harry Potter and the Prisoner of Azkaban wasn't enough. Everyone, please click to read the novel!
Well, it could involve a spell gone wrong during some magical experiment. Maybe a misfired charm that had unforeseen consequences on Hermione's body, leading to the pregnancy. The story might then focus on how she copes with this unexpected situation, both physically and emotionally.
There could be many amateur fanfic authors out there who might have written such a story. It's hard to pinpoint just one. There are numerous fanfiction platforms where people with a creative streak and a love for the Harry Potter universe might have come up with this idea.
Well, in most fanfictions like this, it could be a made - up spell. Maybe something like 'Femina - Transformo' that Hermione has created or discovered in a hidden book. But it really depends on the specific fanfic writer's imagination.