Would you still pay a sitter if you had to cancel last minute?

I had to take my son to the ER and texted before she needed to leave but it was very last minute and she still showed up because her phone was on silent. She’s coming again today and I’m going back and forth on whether to still pay her for that time. I’m a single mom and have her come for about an hour-hour 15 for me to have a therapy session. She’s also pregnant and not in the best financial situation either. I feel like I should still pay her for the missed day, I still get paid for my work when something comes up and it wasn’t anything in her control at all. Is this typical for babysitting? I’m not sure, I know with when I babysat or nannied (aside from my current job) if the hours weren’t put in, I wasn’t paid for them whether it was something on my end or the others. Thoughts? This is the first babysitter I’ve hired.