title: Umbilical artery flow velocity waveforms following maternal exercise.
abstract: The effect of acute exercise on pregnant women in the last trimester of pregnancy and the changes in fetal umbilical artery flow velocity waveforms were studied. One hundred and forty-three healthy pregnant women underwent an acute exercise test. The exercise was performed on an upright bicycle ergometer for 5 minutes, followed by 30 minutes of recovery. The baseline control values of umbilical artery velocity waveforms were compared with those after exercise. The mean exercise intensity achieved was 67.4% (55-90%) of submaximal exercise. Maternal heart rate rose significantly from a mean of 89 (68-120) beats per minute at rest to a mean of 144 (116-200) beats per minute after exercise (P<0.001). Maternal blood pressure rose significantly after exercise from a mean systolic of 112 (80-150) mmHg to a mean of 147 (120-200) mmHg (P<0.001), and from a mean diastolic of 67 (40-85) mmHg to a mean of 84 (70-100) mm Hg (P<0.001). The mean fetal umbilical pulsatility index (PI) was shown to decrease significantly following exercise at 2 and 4 minutes of recovery. It is concluded that (1) an acute exercise test of this intensity causes a significant decrease in PI index after 2 and 4 minutes of recovery; (2) an exercise intensity between 55 and 75% causes a decrease in the PI after exercise while exercise of 76-90% of submaximal exercise causes a rebound increase after an initial decrease at 2 minutes; (3) it may be possible to use this pattern of exercise as an exercise test to differentiate between low- and high-risk pregnancies. Studies on high-risk pregnancies are being prepared for publication.
authors.affiliation: Kent & Canterbury Hospital, UK.
authors.forename: N M
authors.initials: NM
authors.lastname: Rafla