One great 'TVD Caroline pregnant' fanfiction is 'Caroline's New Chapter'. It beautifully explores Caroline's journey through pregnancy while dealing with the supernatural world around her. The author does a wonderful job of portraying her strength and the support she gets from her friends.
There are many interesting fanfictions on this topic. Some might focus on how they deal with the pregnancy in the dangerous world of vampires and werewolves. For example, they could be facing threats from other supernatural beings who see their unborn child as a threat or a powerful asset.
The theme of sacrifice is often present. She may have to sacrifice her own desires or safety for the sake of her unborn child. In some fanfictions, she might even have to make difficult choices between her love life and the well - being of her baby, all while dealing with the vampires, werewolves, and witches that populate Mystic Falls.
Another theme is protection. Given the dangerous nature of their world, protecting the unborn child from various threats is often a central plot point. Enemies might try to harm the baby because of its potential power or to get revenge on Caroline and Klaus.
Caroline could also be in awe. Maybe she has always been curious about Klaus's wolf side and now that she sees it, she is both amazed and a little bit confused. She might stand there, frozen for a moment, just taking in the sight of him in this new form.
Bonnie would probably be very protective. She would use her magic to ensure Caroline's safety during the pregnancy. She might also be the one to encourage Caroline to be strong and not let Klaus's absence break her. Elena, on the other hand, would be more empathetic, sharing her own experiences of heartbreak and trying to help Caroline through the emotional turmoil.
Klaus would be very attentive to Caroline's pregnancy cravings. He'd see it as his duty to take care of her during this time. He might cook for her himself if he can, or take her to the best restaurants to get what she wants. He would be a bit overprotective too, making sure that whatever she eats is of the highest quality and safe for her and the baby. He'd also listen intently to her when she talks about her cravings, finding it endearing and a sign of the new life growing inside her.
Klaus might be overjoyed. He has always been attracted to Caroline, and having a baby with her could be the ultimate sign of their connection. He would probably be very protective, using all his power and resources to keep her and the unborn baby safe.
Elena might be a bit shocked at first but then would be very supportive. She would offer her own experiences and advice, even if they are from a human perspective. Bonnie could be worried about the magical implications of a vampire pregnancy and offer to use her magic to keep an eye on the baby's development.
At first, he might be shocked and a bit scared. But then, Klaus would probably become extremely possessive and overprotective. He'd use his power to surround Caroline with security. He might also be a bit more tender towards her than usual, as he realizes the importance of the new life they are about to bring into the world.