In some fanfics, Sasuke might initially be shocked. He could then feel a mix of joy and fear. Joy because he's starting a family with Sakura, but fear because of the responsibilities and potential dangers that might come with it.
Often, Sasuke in the fanfic would have a complex reaction. At first, he might not believe it. But once it sinks in, he would start to plan for the future. He could start thinking about how to raise the child in a world full of challenges and also how to balance his own life goals with being a father.
Sasuke would likely first show a stoic exterior when he finds out. However, internally, he's in turmoil. On one hand, he's happy that he and Sakura are going to have a child. On the other hand, he's worried about the potential dangers his family could face because of his past enemies. So, he might start making plans to keep them safe, like finding a more secure place to live.
He might be overjoyed at first. Castle has always been deeply in love with Beckett, and a baby would be like a new adventure for them. He'd probably start making plans right away, thinking about baby names and how to turn one of the rooms in their place into a nursery.
In some fanfictions, Vegeta is initially shocked. He might stand there in silence for a moment, his eyes wide. Then he could feel a strange mix of emotions, like pride and fear. He's proud to be having a child with Bulma but also fears for the safety of his family given his dangerous past and the many enemies he has.
He would likely be initially shocked but then filled with joy. He might become very protective, using his skills to keep the pregnant person safe from any harm in the dangerous Middle - earth setting. He could also start making plans for the future, like finding a safe place for the family to live.
She might be initially shocked. Sakura has always seen Naruto as a friend, so learning of his romantic feelings could completely change her perspective of him. It could make her re - evaluate all their past interactions.
There are fanfics where Sasuke is a bit more reserved in his reaction. He may not show extreme emotions outwardly but instead, internally he's filled with a mixture of excitement and fear. He might start thinking about all the responsibilities that come with having a child and how his life as a ninja will need to change to accommodate this new addition to his family.
Well, in this kind of fanfic situation, Sakura could also become more protective of Naruto. Since a jinchuuriki is in a rather dangerous position, she might start to see him as someone who needs her support more than ever. She could try to keep his secret safe from those who might want to harm him because of it.
He might be initially confused. Sasuke is not used to Sakura ignoring him as she has always been somewhat persistent in her attention towards him. So, he may be at a loss as to why she is suddenly acting this way.
He could initially be in disbelief. However, as the reality sinks in, Sasuke would start to show his softer side. He might be more attentive to Sakura's needs, like making sure she eats well and rests. He would also start thinking about how to train their child to be a strong ninja in the future, while also wanting to give the child a more peaceful life than he had.
Sasuke might initially be shocked. He has always been a bit aloof and focused on his own goals. But once the shock wears off, he would probably feel a sense of protectiveness over Sakura and their unborn child. He'd start to think about how to keep them safe in the dangerous ninja world.