Another potential antagonist could be Cameron's own family. Maybe they have different plans for her and don't approve of House's influence on her decision - making regarding pregnancy. They could try to interfere and keep her away from House.
There could be a fellow doctor who has feelings for Cameron. This doctor could see House's attempts to get Cameron pregnant as a threat to their own relationship with her. So, they might try to sabotage House's plans and win Cameron over for themselves.
It could be the hospital's administration. They might oppose the idea of Cameron getting pregnant, either because they think it'll affect her work performance or because they don't want any drama in the workplace.
It could be some of the hospital's board members who might not approve of their relationship and Cameron's pregnancy while working at the hospital. They could try to make things difficult for the couple.
One possible storyline could be that House, in his own complex way, realizes he has deep feelings for Cameron and secretly hopes she'll get pregnant as a way to tie her to him. Maybe he starts dropping hints or acting in a more protective manner around her.
One possible plot could be that House realizes his deep emotional connection with Cameron over time. He might start having dreams about a future with her and a baby. At first, Cameron could be hesitant as she knows House's complex personality. But gradually, through shared experiences and House showing a more vulnerable side, they could start considering the idea of having a baby together.
The Capitol could still be the main antagonists. They might see Katniss's pregnancy as a threat, either because they fear the child could grow up to be a symbol of resistance like Katniss or just because they want to maintain control over her. They could try to harm her or the baby in some way.
House's health issues could be a major challenge. His leg pain and possible drug - related problems might make Cameron question if he can be a stable father. Financially, while they are both doctors, raising a child is expensive. There could also be social challenges, like how their colleagues and friends will react to their decision. And House's lack of experience with healthy emotional relationships could be a stumbling block in building a family with Cameron.
The main antagonists could be some of the other gods who are jealous of Aphrodite's special situation with Percy. For example, Hera might not like the idea of Aphrodite having a child with a demigod, as it goes against the normal order of things in the godly realm.
It could be an ex - partner of either Leah or Jasper. For instance, if Jasper has an ex - girlfriend who is jealous of Leah and the new baby, she might try to cause trouble between them. Maybe she spreads false rumors about Leah to make Jasper doubt her.
Their friends could also be antagonists in a sense. For example, if there's a friend who has always had a crush on Freddie and is jealous of Sam. This friend could spread rumors about Sam being a bad influence or try to convince Freddie that he's making a huge mistake by staying with Sam and having a baby. Another scenario could be that their friends don't take the situation seriously and keep pressuring them to act like they used to, which makes it hard for Freddie and Sam to focus on the pregnancy.
Another possibility is a group or organization that has different ideals. If Thalia and Luke are part of a group that values something different from them, that group could oppose their decision to have a child and become the main antagonists, trying to stop the pregnancy or take the baby away once it's born.
It could be Sharpay's over - controlling mother who is more concerned about her daughter's image and career than the pregnancy. She might try to convince Sharpay to take certain actions that are not in the best interest of the baby or Zeke.