We don't know a lot about this woman. They never say her name in the premiere (although it seems to be Jane, based on the credits), and we only know her husband's name is Bill. She does offer a threat, should anything happen to her husband: "I swear, I will make you all lose your medical licenses. I will shut this hospital down."
We also know that the baby she's having with Bill is male, or at least was born male. (Hey, we don't want to make any assumptions.) Bill says, "How's our son doing?" just before he goes under for his procedure.
So, who could the pregnant woman be? Initial and obvious guesses would be Dean Munsch or Nurse Hoffel. They both seem to be around that age, and they both seem to have something sinister up their sleeves.
