The plot could take a turn when it's revealed that Bella's pregnancy is part of a much larger conspiracy. For example, there could be a group that wants to use her unborn child for some dark purpose. This would completely change the direction of the story as Bella has to not only deal with the pregnancy but also protect her unborn baby from these unknown threats.
A possible plot twist could be that the father of the baby is not who Bella initially thought. Maybe she was deceived in her previous relationship, and when she discovers the truth, it adds more chaos to her already complicated situation in Forks.
One interesting plot twist could be that Bella's pregnancy has some sort of supernatural element to it. Maybe the baby has special powers or is a key to unlocking a hidden world. This would bring a whole new dimension to the fanfiction as Bella has to figure out what's going on with her pregnancy while also living in Forks and dealing with the normal challenges of a small - town life.
One idea could be that Bella has a brief encounter with someone before arriving in Forks and discovers she's pregnant. She then has to deal with the shock and the secrecy while also starting a new life in Forks. Maybe she's worried about how the townspeople will react and how it will affect her future relationship with Edward, if she still meets him in this scenario.
One possible plotline could be that Bella leaves Forks due to some conflict or misunderstanding while being pregnant. She might then try to build a new life on her own, facing the challenges of single motherhood.
Often, a plot twist might involve the nature of the baby. In some fanfictions, the baby could have powers that are not just a combination of vampire and human, but something entirely new. It could be a power that is so strong it attracts other supernatural beings, not just vampires. This would change the dynamics as Bella and Edward would have to protect the baby from new threats.
Well, in this kind of fanfiction, a plot twist could be that an outside force tries to drive them apart by making them believe false things about each other. Maybe they are both in love with the same person, which creates a huge rift between them. Or there could be a situation where one of them sacrifices themselves for the other in a way that no one expected, completely changing the dynamic of their relationship.
A really interesting plot twist could be that Bella's pregnancy progresses at an extremely fast rate, and the baby has powers that allow it to communicate with Bella and Edward telepathically even before it's born. This causes them to reevaluate their relationship and what they thought they knew about vampires and half - vampire children.
Perhaps Bianca gets into an accident and there are concerns about the baby's health. Drew has to struggle with his fear while trying to be strong for Bianca. Or, there could be a misunderstanding where Drew thinks Bianca doesn't want the baby anymore because of some miscommunication, which causes a rift between them until they clear things up.
Well, usually when Bella is pregnant and moves to Forks in fanfiction, it triggers a cascade of events. It could involve conflicts with the local vampire or werewolf communities, or have an impact on her relationships with the characters around her. Sometimes, it even changes the entire power dynamic of the story.
One possible plot twist could be that Bella discovers Caius has a hidden agenda all along, and it's not just about their relationship. Maybe he's using their bond to gain power within the vampire world. Another twist might be that Bella has a secret power that is awakened by her connection with Caius, and this power changes the dynamics of their relationship and the entire vampire community.
I'm not sure specifically which 'bella leaves forks pregnant fanfiction' is out there. You could try searching on popular fanfiction websites like Archive of Our Own or Fanfiction.net. Just type in the relevant keywords in their search bars.
One possible plot twist could be that the pregnancy is not as straightforward as it seems. Maybe there are some magical or supernatural elements involved in Bella's pregnancy that Will has to figure out. For example, it could be that an ancient spell has been cast on Bella which causes her pregnancy, and this spell has some hidden intentions or consequences that will unfold throughout the fanfiction.