Continuity mistake: Roseanne becomes pregnant at the beginning of Season 7, and it is before the Halloween and Thanksgiving episodes, so she is in her first trimester during the holidays. However, Roseanne does not give birth until the following year in the Season 8 Halloween episode. Her pregnancy has lasted for well over a year.
Factual error: 1/4 through the show, Darlene, Becky, David and Becky's husband, Mark, are playing Scrabble. Mark puts down "oxygen" on the board in the lower corner with the "O" covering the triple word square. David is counting up the score and says the "X" is on the triple letter box, and totals the points up to 99. The problem is there is no triple letter box next to the triple word box or even on the outside edges of the board.
Character mistake: When Roseanne, Darlene, Jackie, Bev, Becky, and Nana Mary are dressing for Darlene's wedding, Nana Mary comments that all of them were pregnant when they married. However, Becky, was not pregnant when she and Mark eloped and they never had children together. Roseanne was not pregnant before marrying Dan. When the series began, Becky was 13 years old and Dan and Roseanne had been married 15 years.