You do just that, specifically to Rarity, saying that you would be with Shimmer for the longhaul.
Rarity: phone buzzes Hm? *pulls out phone and reads message out loud:
Ted: Shimmer is doing ok for now, I’m going to be staying with her.
Twilight: Should we come back another time then? It sounds like we’re not needed right now.
Pinkie Pie: And miss seeing the new twins?? I don’t think so, I’m staying!
Rainbow Dash: still rocking her baby girl on her lap Have you forgotten how long labour lasts? Me and Twilight spent an entire day in active labour!
Applejack: I don’t know, maybe I should stay, I want to be there to congratulate her.
Fluttershy: It will take as long as it can. Please be OK, Shimmer.
Back in your room, you’re currently holding Shimmer’s other hand during her contraction with your opposite hand giving the left one a break. You needed some distraction to keep her motivated. You spot a stethscope hanging on the door and get an idea.