These episodes could be uterine contractions.
Count the fetal movements regularly (I know, you do), If any abnormal decrease / increase is noticed - go to obstetrician immediately. You are now at term gestation, and your fetus is mature.
It could be due to / cause fetal distress
. It is important to monitor fetal heart rate
.Visit your doctor now, get you and your fetus examined. It could be necessary to get the baby delivered (vaginal or caesarean) as your doctor advice
Don't wait much, perinatal asphyxia
is very dangerous for your baby.