Baby's heart rate is high

Brandi
Went in today for my 38 wk appt.. 2cm dilated buuuut baby girl's heart rate is high and doctors a bit worried..wants me to go back tomorrow to check on her and if her heart rates still high then he's sending me over to the hospital to see whats going on. Has anyone else experienced this? What happened? What caused babys heart rate to be elevated?