Despite the trivia post stating that Nancy Dussault was actually pregnant so it was written into the show is untrue. The actress was not pregnant and in fact was unhappy about the baby being written into the show. If you check Nancy's IMDb profile, it states married twice, no children.
In most episodes, Ted Knight wears different college sweatshirts sent in by fans. In episode 2.1, he wore an Ohio State University sweatshirt. He later wears a different USC sweatshirt in episode 3.5.
Nancy Dussault (Muriel) was really pregnant, so her pregnancy was written into the series.