One idea could be to focus on Bella's inner thoughts during the birth. Maybe she reflects on her journey from a normal girl to a vampire's mate and how this new life she's bringing into the world will fit into their supernatural existence. For example, she might worry about the baby's safety in a world full of vampires and werewolves.
You can make it unique by changing the setting. Instead of the normal hospital or Cullen house setting, have it in a more remote and magical place, like a hidden glen in the forest that has some special properties that affect the birth. Maybe the magic of the place gives the baby some unique abilities right from birth.
The scene was in a quiet barn. Bella lay on a bed of straw. She was surrounded by soft light. As she gave birth, her breathing was heavy. Puppies started to appear, wet and small. She immediately started to care for them.
Once upon a time, Bella, a beautiful and gentle dog, was about to give birth. Her owner had prepared a warm and cozy corner for her. As the time came, Bella started to pant heavily. With every contraction, a tiny puppy emerged. In the end, she gave birth to five adorable puppies, and she licked them clean with love.
Some Bella giving birth fanfiction stories may explore different scenarios. Maybe it's a difficult birth that makes everyone worry about Bella's life. This kind of story often builds a lot of suspense. The author might describe in detail the medical procedures and the efforts of the doctors (if there are any in the fanfiction world) to save both Bella and the baby.
The Cullen family usually plays a significant role. Carlisle, with his medical knowledge (even if it's vampire - related in the Twilight context), might be involved in ensuring a safe birth. Alice could be there, perhaps using her gift to foresee any potential problems during the birth. Even the other members of the Cullen family would be around to offer their support in different ways.
Well, it could be about the challenges Bella faces during the birth, like the pain and fear. Maybe it also shows the support she gets from her family or friends around her.
One possible scenario could be that there were complications during the birth that couldn't be overcome. Maybe there was excessive bleeding or an undetected health issue that led to her death.
Well, a plot twist might be that the baby has a special connection to an ancient vampire clan that no one knew about. This could lead to a whole new storyline where they try to claim the baby. Also, Bella could experience a vision during the birth that reveals a future event that changes the course of the 'Twilight' world. Maybe she sees a great war coming and this knowledge makes everyone around her change their plans. It could also be that the baby's birth causes some sort of magical ripple effect that starts to change the abilities of other vampires in the area.
She might be portrayed as a villain by showing her being manipulative. For example, she could use her relationship with other characters to get what she wants, like using Edward's love for her to control his actions or decisions.