Their relationship would likely become more intense. With a baby on the way, there's a new level of commitment. Damon might become more tender and less reckless, as he now has Elena and the unborn child to think about. Elena would probably rely on Damon more, trusting him to protect her and their future family.
One idea could be that they face challenges from the vampire and werewolf communities. Since their relationship was already complex in the show, this pregnancy could stir up more trouble. Another plot could be them trying to keep the pregnancy a secret while preparing for the arrival of the baby. They might have to deal with issues like finding a safe place to raise the child in a world full of supernatural threats.
Love and family are common themes. Their love for each other deepens as they anticipate the arrival of their baby. Family also plays a big role as they think about how their families will react and how they will create a new family unit.
Their relationship would likely become more serious and committed. With a baby on the way, they'd have to think about the future more. Damon might become more protective of Elena.
One popular storyline could be how they deal with the challenges of being new parents in a world full of supernatural threats. For example, they might have to protect their unborn child from other vampires or werewolves who see the baby as a threat or a valuable asset. Another could be the emotional journey they go through, like Damon's fear of being a bad father due to his past, and Elena's determination to make their family work. There could also be a storyline where they discover unique powers that their child might have, which adds an element of mystery and adventure to the fanfiction.
Elena would be devastated when Damon leaves her pregnant. She has always had a complex relationship with him, and this would be a huge blow. She might isolate herself at first, not wanting to share her situation with others. But as the pregnancy progresses, she would start to realize that she has to be strong for the baby. She would draw on her inner strength and the memories of the good times she had with Damon to find the courage to face the challenges ahead. She might also experience moments of hope, thinking that Damon could come back someday, but she would not let that hope consume her and would instead focus on building a life for herself and her child.
Well, a possible plot is that Elena's pregnancy is the result of a spell gone wrong. Klaus, despite his initial shock, decides to stand by her. This could lead to a series of events where they have to fight off those who see the baby as a threat. It could also explore how Elena deals with the physical and emotional changes of pregnancy while being in a rather strange relationship with Klaus. And the baby might have some unique abilities that are both a blessing and a curse.
Yes, there are likely many Vampire Diaries fanfics out there where Elena and Damon are pregnant. Fanfiction writers often explore different 'what - if' scenarios in the Vampire Diaries universe, and the idea of Elena and Damon having a child is an interesting concept for many fans to write about. You can find such fanfics on various fanfiction websites like Archive of Our Own or FanFiction.net.
One idea could be that Damon is initially terrified of becoming a father but then gradually embraces the role as he sees Elena's excitement. Another could be that they face threats from the supernatural world because of the unborn child, like vampires or witches who want to use the baby's power. Maybe there's a prophecy about their child that causes all kinds of chaos in their lives.