In the final episode of School Days anime, Sekai said that she was pregnant. Her behavior seemed like she was telling the truth.
However, when Kotonoha offered Sekai to consult at the hospital, she refused to go. This made Kotonoha suspect that Sekai was lying. And when Kotonoha stabbed and dissected Sekai, Kotonoha confirmed her suspicion.
But even before her death, Sekai stated clearly that she was pregnant, though she didn't have to lie to Kotonoha anymore as Makoto was already dead.
So was Sekai really pregnant or not?