I would absolutely agree with Lulu on the fear part of it.... Did something change for her at that point in time? Something she may not have realised would affect her so much?

This exact thing happened to me & I can pinpoint exactly where it went wrong. I was at 9cm with Alexzander & everything was going perfectly. I had been in labour for 29 hours at the time (had the drip & epi in for 4 hours by then) and everything stopped, I remained at 9cm for another 7 hours until I was given a c/s. I put it entirely down to a midwife change over. I was very comfortable with the midwife I had, she was there with me from 7am to 7pm and just was not allowed to stay with me anymore, as it was she had already stayed 4 hours over her shift at that point. When she left it stalled. I was at ease with her & the next midwife I didn't click with. I hadn't realised it at the time, but a while afterwards I figured it out.