Continuity mistake: In the last movie, half of Chucky's face was sliced off by the giant scythe in the tunnel at the carnival, but in this movie, after being repaired, he seems to have a whole stitched up face, when half of it shouldn't be there.
Continuity mistake: In the previous 3 films Chucky has painted on eyebrows, in this one they're hair. Since this is the same body he had in part 3 they should be painted.
Answer: Considering the voodoo involved, and the fact she got pregnant as a doll, this is not a normal pregnancy.
MasterOfAll