Yug Ylimaf - S11-E4
Factual error: Near the end when Stewie is being put back and out of Lois's womb, he has no umbilical cord attached to him.
Factual error: There's no way for the Griffins to climb clear to the top of Mt Everest. It takes months to prepare for that and oxygen tanks. This episode is one whole factual error. That and it costs 30 grand or more per person.
Answer: Lacey Chabert was the actress who originally voiced Meg in early episodes. She left of her own accord due to being in school and other acting work; Seth MacFarlane has stated there was no tension with her leaving, but it makes for a handy joke for the show.