Continuity mistake: In the end when they are in the hospital and Amy is talking with Stu about the proposal, in all the shots Amy's necklace is on the outside of her shirt. Then Peter comes in to tell them about the birth and Amy walks over to him and embraces him. In the shot right after the hug the necklace is inside her shirt, although she didn't have time to put it inside.
Continuity mistake: In the scene when Kyle comes to Peter's office to talk about the baby, Kyle's hair changes from shot to shot. When sitting down there is one wisp of hair standing up horizontally at the left side of his head. In the next shot it disappears, then appears again.