Factual error: When Kate is driving Angie to the hospital to deliver her baby, she is going over the Ben Franklin Bridge towards Camden in New Jersey. However, the next morning, the exterior shot of the hospital at which Angie is staying shows a sign saying "The Hospital of the University of Pennsylvania," which is in Philadelphia, not New Jersey.
Revealing mistake: When Angie is having her ultrasound, if you keep an eye on the monitor, you can see that the baby shows up before the doctor places the reader on Angie's stomach.
Other mistake: In two separate scenes the same item is used. One at Angie's apartment, when Kate drops her off after the procedure, as soon as they get to the top of the steps and turn the corner there is a sconce visible on the wall with no candle... Later that same sconce is in Kate's apartment (in the scene where Oscar is drinking a red-bull, it is to the left of him).
Continuity mistake: When the pea-soup is first taste tested, you can see close up that it is under C. Once it zooms out to the room, it seems B and C have changed places.
Factual error: When Kate gives Angie a ride back to Kate's house/apartment, the outside scene shows a road sign for PA-51. PA Route 51 is a road in southwestern Pennsylvania, not a road near Philadephia, which is where the film is set.