During the case (between Brandon and Brittany) there is a shot that shows blood on the back of Brittany's coat. This isn't possible, because she has never been attacked.
During the phone conversation between Brandon and Brittany Brandon's iPhone shows the home screen.
During one shot of the chase scene where Brandon is chasing Brittany through the woods, Brittany appears to be briefly wearing tennis shoes instead of ballet flats which she is wearing throughout the rest of the scene.
In the opening sequence the nurse states "7 births in one hour, all premature". Later it is revealed that Bug was not born in the hospital, and was not one of the 7 babies the nurse referred to. The existence of the unknown 8th baby is never referenced anywhere else in the film. Its possible however that bug was rushed to the hospital ahead of Abel and Patterson and had already arrived when the crash occurred, and that the nurse mistook him for another premature birth.