When Barry and Ginger are in the doctor's office, the doctor states that the due date is December 10th. This would be about one month longer than expected since the conception date was February 11th. This would be a ten month pregnancy rather than the usual nine month time frame.
When Barry and Ginger are having sex, Barry points out a smiley face tattoo that Ginger has on her left leg, which Ginger said she got in college. But in a previous scene, before Ginger was to give birth, there is a clear shot of her left leg and no sign of any tattoo.