This probably isn't quite the same thing, but this was my experience.

I went in for my check-up at 41 weeks and the hooked me up to check on bubs heart rate. It was strong and healthy most of the time, but occasionally dropped quite dramatically. They kept me on the monitors for hours and hours, before finally deciding to induce me (since I was 41 weeks already anyway). Inducing however made bubs worse, and his heart rate started dropping more often and for longer. I ended up with an emergency c/s.

I think it's sudden drops that are probably more of a problem than a consistent but slower heart rate, iykwim?