Heres is my guess, the tests actually showed that Anu is pregrant and not Bani. Since Bani considers Anu as her younger sister, she will do anything to protect her and so thats y she's not saying anything to anyone. All the doctor said was Mrs, Walia is pregrant,and Rano was the one who said that Bani wasn't feeling well so assumptions were made.
Let me know what do u all think?