SOOKIE: Oh my God, I’m pregnant! …
RORY: That’s great!
[they all scream and hug]
Lorelai suggests to Sookie she may have some kind of minor illness affecting her taste buds, then she goes into the lobby to talk to Rory, before Sookie comes out of the kitchen and announces she’s pregnant.
Pregnancy can certainly affect the sense of taste of smell, explaining Sookie’s suddenly horrible food, so this makes sense – but how can Sookie be sure? Did she just throw up in the toilet (which could be something else), did she do the world’s quickest pregnancy test, and if she had one all along, why didn’t she use it before? Has she had some other little sign, like her periods stopping, breast tenderness, and weight gain, and she’s put all the clues together?
Who knows? She just apparently knows she’s pregnant, even though she’s seemingly never been pregnant before, and everyone gets super excited and jumps around hugging each other. Nobody asks Sookie how she knows, or suggests she might be mistaken, or that it might need to be verified by, oh I don’t know, science.