She might want to prove herself in a male - dominated ninja world. If she shows herself as female, she could face discrimination or be underestimated. So, hiding her gender gives her a chance to be seen as an equal to male ninjas.
Well, she could start by dressing in a more androgynous way. Maybe wearing loose-fitting clothes that don't give away her feminine shape. Also, she might try to lower her voice or use certain speech patterns that are more associated with males in that fictional world.
Perhaps Naruto is waiting for the right moment to reveal his skills for maximum impact. He could be planning a big surprise for his enemies or wants to make a grand entrance at a crucial time. For example, in a major battle against a powerful foe, he could suddenly unleash all his hidden skills and turn the tide of the battle, which would be more effective than showing them off gradually.
One reason could be for self - protection. In a dangerous or hostile environment within the fanfiction world, hiding gender can keep Sakura safe from potential threats.
He might want to protect himself. If others know how smart he is, he could become a target. Enemies might see him as a greater threat and go after him more aggressively.
The story's plot could also take different turns. Instead of the usual challenges he faces as a male ninja, he now has to deal with issues related to hiding his gender. This could include things like disguising his appearance more carefully and avoiding situations where his gender might be discovered.
Well, in such fanfiction, one idea could be that Naruto hides his gender to gain an advantage in a male - dominated ninja world. Maybe he feels that as a female, he'd be underestimated or treated differently. So by hiding it, he can prove himself on equal terms.
Maybe he wants to protect his loved ones. If his enemies know his true strength, they might target his friends and family to get to him. So, by hiding his skills, he can keep them out of harm's way while still being able to fight when necessary.
One possible reason could be that he is on a secret mission and doesn't want to be recognized. He might be infiltrating an enemy organization or spying on someone. Another reason could be that he has some new power or mark on his face that he wants to keep hidden until he fully understands or masters it.
Maybe she wants to avoid causing unnecessary worry among her friends and comrades. They are often involved in dangerous missions, and if they knew she was pregnant, they might get distracted. Naruto might think it's better to keep it a secret until she figures out how to handle the situation without disrupting their important work.
Another possibility is that Naruto has a plan that requires him to keep his skills hidden from everyone, including Hinata, for a while. He could be waiting for the right moment to reveal them and use them to surprise and save the day, especially when it comes to protecting Hinata from a big threat that he anticipates.