A worried pregnant mom with a young daughter in a horror movie?
I believe this movie is no more than 10 years old.
Like a lot of horror movies and books, the main character is a pregnant woman who is worried about the presence of evil in the home. Her husband scoffs at her fears, but her little girl, who is probably about eight years old, is sympathetic to her concerns.
But later in the movie the woman happens to mention something the daughter said and her husband gets really upset. Turns out that the little girl is ghost or figment of her imagination, their daughter really having not survived infancy.
Ring any bells?