Well, one possibility could be that Naruto is in hiding because he has discovered a new and powerful enemy that is targeting him specifically. He might be training in secret to gain even more strength to face this threat. Maybe he's also gathering allies in the shadows who are willing to fight with him when the time comes.
It's possible that the antagonists are from another dimension. They have sensed Naruto's growing power and want to stop him before he becomes too strong. They are using their unique abilities to track him down while he's in hiding. These antagonists could have powers that are completely foreign to the ninja world, making them very difficult to defeat.
One consequence could be that his friends might start to suspect him. Since Naruto is usually an open book, hiding something as significant as his eye could make them wonder what he's up to.
Another likely antagonist could be a rogue group within Naruto's village. They might have turned against the village's values and see Riasa as a means to an end, like using her as a bargaining chip with other villages or for some personal gain.
I'm not sure specifically if there is a fanfic exactly titled 'sakura hiding pregnant'. There are so many fanfics out there in various fandoms that it's difficult to say for certain without a more in - depth search through relevant fanfic platforms.
Well, perhaps the main plot could be centered around protecting Riasa from some sort of danger. Maybe there are enemies after her, and Naruto, Kiba and Issei have to use their unique skills to keep her hidden. Naruto could use his shadow clones to create diversions, Kiba with his dog companions could sniff out any approaching threats, and Issei might have some special abilities to help with the concealment.
I'm not sure specifically as there could be many different interpretations of a 'sakura hiding baby fanfic'. It might involve a story where sakura (could be a character named Sakura) is hiding a baby for some reason, perhaps to protect it from danger or some sort of secret plot in the fictional world of the fanfic.
Well, in such a fanfic, perhaps Bulma might be hiding her pregnancy due to fear of various reasons. It could be fear of how her friends and family will react, or maybe she's worried about the implications it will have on her life. For example, she might be concerned about her freedom being restricted or her scientific pursuits being put on hold.
It could be that they are in hiding to avoid a powerful enemy. This enemy might be after something they possess, like a powerful jutsu or a secret scroll. Naruto and Temari are forced to go into hiding, constantly on the move, and during this time, they develop a deeper understanding of each other and their own powers while trying to outwit their pursuer.
It could be about Naruto achieving his goals more smoothly than he ever thought. For example, he might have mastered a new jutsu way faster than expected. Maybe he was aiming to convince a certain character to join his side, like Sasuke, and it happened with less resistance than he anticipated. This kind of fanfic would be full of positive surprises for Naruto and those around him.