Correcting umbilical artery flow velocity waveforms for fetal heart rate is unnecessary

Citations from the Literature The effect of (induced) mate4 emotions on fetal behaviour: A controlled study Van den Bergh BRH; Mulder EJH; Visser GHA; PoelmannWeesjes G; Bekedam DJ; Prechtl HFR Department of Obstetrics, University Hospital, Groningen; Netherlands Early Human Development/l9/1(9-19)/1989/ In ten healthy near-term pregnant women the effect of induced maternal emotions on fetal motor behaviour was studied. Emotions were induced by showing a film of a normal delivery. Fetal behaviour was recorded by means of real-time ultrasound observations of general movements and eye movements and by fetal heart rate monitoring. The observations had a duration of 2 h. The data were compared with those obtained during a 2-h control period, which took place the day before (n = 5) or after the study period (n = 5). Maternal emotions (induced) were measured by means of psychological tests. NO effects on fetal motor activity or on behavioural state organization could be found as a result of this film. There was, however, a significant positive correlation (P < 0.01) between the mean level of anxiety of the women and the motor activity of the fetuses. Vibratory acoustic stimulation and the flow velocity waveform in the fetal interaal carotid artery Wladimiroff JW; Cheung K Department of Obstetrics and Gynaecology, Erasmus University, 3015 GD Rotterdam; Netherlands Early Human Development/l9/1(61-66)/1989/ Eleven healthy fetuses between 36 and 39 weeks of gestation were studied during the active sleep state to examine effects of a 5-s vibratory acoustic stimulus on the baseline fetal heart rate and flow velocity waveform in the fetal internal carotid artery. There was an immediate marked rise in baseline fetal heart rate with concomitant drop in pulsatility index in the flow velocity waveform of the fetal internal carotid artery, which persisted for at least 15 min after the stimulus. However, when the pulsatility index was standardized for a fetal heart rate of 140 beats/ min this index remained virtually unaltered. These data suggest that in the healthy term fetus during active sleep state, a vibratory acoustic stimulus has no measurable effect in cerebral vascular resistance. Since virtually all reported studies on vibratory acoustic stimulation of the fetus were carried-out during the quiet sleep state, the data from the present study do no provide any information on the safety of this device when employed as a means of assessing of fetal well-being. Nonstress testing with acoustic stimulation and amniotic fluid volume assessment: 5973 testswithout unexpected fetal death Clark SL; Sabey P; Jolley K Utah Valley Regional Perinatal Center, Provo, UT 84603; USA American Journal of Obstetrics and Gynecology/l60/3 (694697)/1989/ In a 36-month period antepartum testing was performed 5,973 times in 2,628 women with singleton high risk pregnancies. The testing scheme involved a modified nonstress test with

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sound stimulation. Testing was performed twice weekly for patients with diabetes (classes B through R), gestational age exceeding 42 weeks, and documented intrauterine growth retardation, and weekly for other indications. If no spontaneous acceleration was observed within 5 minutes, a single 1- to 2second sound stimulus was applied to the lower maternal abdomen with an artificial larynx. If necessary, a second sound stimulation was applied within 10 minutes. In addition all patients received ultrasonographic four-quadrant assessment of amniotic fluid volume. The mean testing time was 10 minutes. Only 2% of tests were nonreactive with sound stimulation. Seventeen percent of nonstress tests that were nonreactive with sound stimulation were followed by positive results of a contraction stress test or a biophysical profile score 64. The overall intervention rate was 3%. All fetuses with a single acceleration only eventually met criteria for negative results to a contraction stress test or had a biophysical profile score >8. There were no unexpected antepartum fetal deaths. Sound-induced accelerations appear to be valid in the prediction of fetal well being, and the use of sound stimulation results in a significant shortening of testing time. Simultaneous assessment of amniotic fluid volume may reduce the risk of fetal death to a negligible level. Correcting umbilical artery flow velocity waveforms for fetal heart rate is unnecessary Kofinas AD; Espeland M; Swain M; Penry M; Nelson LH Department of Obstetrics and Gynecology, Bowman Gray School of Medicine, Winston-Salem, NC 27103; USA American Journal of Obstetrics and Gynecology/l60/3 (704707)/1989/ We prospectively examined 55 normal pregnant women between 32 and 41 (R = 37) weeks’ gestation. Five measurements of the umbilical artery peak-systolic/enddiastolic frequency ratio were obtained from each patient during one examination. Comparison of the fetal heart rate and the umbilical artery peak-systolic/end-diastolic frequency ratios between pregnancies < 37 and >37 weeks’ gestation revealed no difference. Subsequently a total of 256 measurements were analyzed as one group. Plotting the individual peak-systolic/end-diastolic frequency ratios against the corresponding fetal heart rates revealed a moderate negative linear correlation: y = 4.15 -0.012x, r = -0.36 and p < 0.04. When only heart rates between 120 to 160 beats/min were plotted against peak-systolic/end-diastolic frequency ratios, a weaker correlation was found (r = -0.33, p = 0.15). The difference (mean * SD) between the obtained and the corrected peak-systolic/end-diastolic frequency ratios was 4.4% f 3.2%. The 95th percentile of the obtained peak-systolic/ end-diastolic frequency ratio was 3.35 and the corrected ratio was 3.27. Averaging of the five measurements obtained from each patient for all 55 patients decreased the 95th percentile value to 3.09 whereas the same procedure for the corrected peak-systolic/end-diastolic frequency ratios decreased it to 3.07. We conclude that although there is a statistically significant negative linear correlation between the fetal heart rate and the umbilical artery peak-systolic/end-diastolic frequency ratio, this relationship is not clinically significant. Int J Gynecol Obstet 30