I was giving my understanding of Armando's criteria for what makes a scene, which is useful but separate from Dramatica. However, as I said, I can usually (I haven't found one yet, where I can't) also see the top tier from Dramatica domains/classes.
I will admit to dragging in my personal puking experience being pregnant...since a male reader would not have that frame of reference (or even all women) I amended the sentence.
In Dramatica for Screenwriters Chapter 14 Armando lays out his criteria for a "true event" To my interpretation the minimum necessary to create a scene, the basic building block of plot.
"I'm pregnant," she said, then puked on his tennies.
You are right, it is the reader who brings importance to the concept. But under no circumstances are those words EVER unimportant. Go ahead find some one anyone who thought they were, I'll wait. No? Didn't think so. Even if you have a character that says "So what, that's on you," and walks away. THAT is a conflict for the character left standing there.
Irreversible - I'm sorry, being pregnant is not something you can, just undo. You have to DO something else if you want to reverse it. Are you deliberately being coy?
And new direction, again...in the context of story, this announcement will pretty much always send the characters in a new direction. Who do they tell, or not tell, do they try and hide it. Do they need to start going to prenatal care, are they in medieval and the local wise woman just croaked. There are natural consequences to being pregnant that will have to be followed up on. So no, I am not just pulling things out of my ass.
Yes, finding out you are pregnant is a new situation -- what conflict the character finds there is dependent on the story being told, but a new sitch still exists -- otherwise why would an author include it. To your example of a woman kept for breeding purposes (which eww, what an ugly example. have you been watching Handmaid's Tale?) Her sitch is most definitely changed, or why make her preggers? You give her jealousy from the others that have not become pregnant, You give her special treatment or food. You give her fear of her child being taken away.
I feel like you think, I think "I'm pregnant." is a story full and complete. And I don't know why you'd think that. I don't think that. But I absolutely believe that it is a full and complete scene based on Armando's criteria and my personal writing experience. It would be one that was part of a sequence, never meant to stand alone, but separated as an emphasis to its importance.
I don't know how to allay your fears for my writing chops. Maybe when I post my short.