I can't remember the name of the manga but I do remember what happened and I was wondering if someone came across that manga.

-Definitely a josei, just might be labeled as smut.
-Possibly a one-shot but I'm not 100% sure.
-The settings was a desert I think and modern technology (Phones, computers, TVs and so) didn't exist.
-Main girl was kidnapped or something.
-She was given a drink which would make a difference in her body.
-Main girl engage in a sexual relationship with main male (I think he was a lord or something).
-Main girl returns home. Girl is the daughter of a lord/government officer.
-Her father summon the guy and asks him about what happened back where they stayed during the time she was kidnapped(was in a palace or something). The father tells him his daughter started sleeping naked lately and that she's pregnant.
-Guy tells the father that it can only be his child and says that he will take responsibility.
-They get married and live happily together. (I think)