Without a clock in the room, without any external stimulus, the passage of time is marked only by Elsa's contractions, marked by her squeezing Anna's hand tight.
The midwife checks Elsa every so often, seeing how far she's dilated. Elsa's had her eyes closed for what feels like hours, breathing laboured as she weathers the pain. She's thrown up a couple of times, exhaustion and pain making her sick.
Anna hasn't asked her about pain relief again.
She hasn't said anything at all, actually. She's just trying to be there for Elsa.