The day progresses steadily, though the labor itself doesn't.
It's perfectly normal for it to take hours. Elsa's already exhausted and she hasn't even started pushing yet. At about dinner time, a nurse comes in to check how frequently her contractions are. They're getting closer and closer, and Elsa has to pause each time to wait it out.
She isn't fully dilated, though, so the nurse asks if she wants to shower or rest a little before the next stage. She's got maybe a couple of hours before she has to start pushing.