There are no rest-activity dependent changes in fetal ductus arteriosus flow velocity patterns at 27–29 weeks of gestation

Blood flow velocity waveforms recorded in the fetal ductus arteriosus were related to fetal heart rate pattern (FHRP) in 13 normal pregnancies at 27–29 weeks of gestation. Recording time was always 65 min or more. In three women no low fetal heart rate (FHRP-A) variability was present, in the remaining 10 women high fetal heart rate (FHRP-B) variability was established in 80% of the recording time. There was no statistically significant difference between FHRP-A and FHRP-B pattern for all ductal flow velocity parameters, indicating restactivity state independency in late second and early third trimester pregnancy.