The church service takes place in the evening but when Jackson, Helen, and Martha return to the farmhouse, it appears to be daytime in the kitchen. The same thing occurs when Helen is talking to Martha in the kitchen late at night while Jackson is sleeping on the couch.
Helen's baby bump appears and disappears. When shes attacked its making her shirt tight, later however, when shes with her husband in the park, her stomachs thin and flat.
When Helen shows the picture to Alice, it is upside down, but in the next shot it is right side up.
When Helen goes to the barn and finds the locket in the drawer, Martha catches her. When Helen hears Martha, she closes her hand around the locket above the open drawer. In the next shot, every drawer in the dresser is closed.
Helen and Jackson get married and then return to New York. This whole time the couple is in New York, Helen is not wearing her wedding ring. When they return to Kilronan, she is wearing the wedding ring. This maybe suggests that the filming in New York took place before they shot the wedding in the country.
Martha attempts to induce Helen's labor by spiking a cake with Oxytocin. We see Helen eat the cake, and then several hours later go into labor. The problem is that Oxytocin is broken down in the gastrointestinal tract and rendered ineffective. It needs to be injected or inhaled to work.
When Martha goes for the Oxytocin box and the camera zooms in on it, it has "Erythromycin tablets" visibly written under "Oxytocin"; erythromycin is an antibiotic.
In the first scene, Johnathon Schaech is driving. When they arrive at their destination, Gwyneth Paltrow is driving with no explanation as to why they changed drivers. Obviously they stopped somewhere along he way and changed seats.
When Helen and Alice are at the retirement home feeding ducks, the shot pulls out and you can see the ducks in the pond at the bottom of the screen. They are swimming in backwards circles suggesting the shot was originally moving in, not out and was reversed.
When Helen is nude, and jumps back into bed after meeting Martha Baring, when the camera changes she is wearing shorts as she covers up in the bed.