No. In general, depicting one character as another's slave in fanfiction is not appropriate. It goes against the values of equality and respect. Characters should be in relationships that are based on positive and healthy interactions, not on a master - slave dynamic which is a form of oppression.
In the beginning, Kurenai might be resentful of her new status. However, Naruto's kindness and his unwavering belief in her as a person could slowly change her perspective. As time passes, their relationship could evolve into a partnership. Kurenai could use her wisdom to guide Naruto in areas he is lacking, and Naruto could inspire Kurenai with his determination. They could end up having a relationship that is far more complex and equal - minded than the initial'slave - master' label implies, with a deep mutual understanding and respect.
It can damage the positive image of the Naruto franchise. Fans may be turned off by such a negative and unethical concept being associated with the characters they love.
The plot could start with a mission gone wrong. Kurenai makes a mistake that endangers the village, and the only way to make amends is to become Naruto's slave as per the village's elders' decision. Naruto, though, doesn't treat her like a slave. Instead, he tries to make her an equal. This causes some conflict within the village as some people believe she should be treated harshly. But Naruto stands his ground, and together they face challenges and grow as characters.
In a fanfiction where Naruto and Kurenai have a baby, the story could explore how the two different clans react. Naruto is from the Uzumaki clan and Kurenai is from the Yuhi clan. Their baby could be a symbol of unity between the two clans. Also, the baby might grow up having Naruto's dream of being Hokage but with Kurenai's teaching skills, which could make for a very different kind of leadership in the village.
Writing such fanfiction is highly inappropriate. It involves treating characters in a demeaning and unethical way, reducing them to the status of slaves. In the Naruto universe, these characters are strong and independent, and this kind of fanfiction goes against the spirit of the original work and basic respect for human dignity.
Naruto would support Kurenai by being her emotional pillar. He has a very empathetic nature, so he would listen to her concerns about the pregnancy, like her fears for the baby's health or how she's going to be a mother. He would offer words of encouragement and tell her she's going to be a great mom.
Rather than the inappropriate concept, a great alternative in fanfiction could be to explore their relationships in a more positive light. For example, Naruto could learn important ninja techniques from Anko and Kurenai, and they could all participate in a friendly ninja competition together. This would focus on growth, friendship, and the ninja spirit.
Well, perhaps in this fanfic, the pregnancy could be a result of a special mission or some sort of magic that binds Kurenai to a character. And Naruto, being the hero he is, gets involved to help Kurenai understand and deal with the situation. He could also help her face the reactions of the village, which might be mixed since Kurenai is a respected shinobi.
Tenten could be one of the characters. She could be Naruto's friend and also have a bit of a crush on him. Ino might also be present, using her mind - related jutsu to try and understand the complex relationships in the harem. Rock Lee could show up too, providing some comical relief and also being Naruto's loyal friend in the midst of all the relationship chaos.