Doppler Velocimetry Versus Nonstress Test in the Antepartum Monitoring of Low-Risk Pregnancies Domenico Arduini, MD, Giuseppe Rizzo, MD, Alberto Soliani, MD, Carlo Romanini, MD"'
One thousand singleton low-risk pregnancies were cross-sectionally studied at 36- 40 weeks gestation with continuous+wave Doppler ultrasonography in order to assess its usefulness as an antepartum monitoring technique for the identification of fetuses at risk of developing an adverse outcome. Uterine artery and umbilical artery S/ D values were measured and related to fetal outcome. Results were compared with those of the nonstress test. No significant differences in fetal outcome, with the exception of birth weight, were found between patients with normal and abnormal uterine
A
bnormal velocity waveforms in the uterine and umbilical arteries seem to be associated with pregnancy complications such as hyperten sion, ' intrauterine growth retardation, 2 and fetal distress,1 and several studies have suggested a potential application of Doppler ultrasonography to predict ad verse outcome in high-risk pregnancies. 4" 6 Few data are available on the significance of Doppler velocimetry in the general population, and the results so far obtained are contradictory. 7•8 This study assesses the accuracy of Doppler velocimetry in the prediction of fetal distress and compares the validity of this technique with fetal heart rate monitoring in a low-risk population.
Received from the Laboratory of Fetal Physiology, Department of Obstetrics and Gynecology, Universita Cattolica s. Cuore, Rome; and "Department of Obstetrics and Gynecology,. Universila di Ancona, Ancona, Italy.. Address correspondence and reprint requests to Dr. Domenico Arduini: 1st Cl. Ostetrica e Ginecologica, Universita Cattolica Cuore, Largo A. Gemelli, 8, 00168 Roma, Italy.
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S/ D values. In pregnancies with abnormal umbilical S/ D values, a higher incidence of cesarean section for feta I distress and lower birth weight were observed. Moreover, those newborns more frequently had complications such as low 5-minute Apgar score, requiring resuscitation and admission to the intensive care unit. When compared to nonstress test, umbilical velocimetry showed a higher efficiency in identifying fetuses at risk for adverse outcome. KEY WORDS: antepartum monitoring, Doppler velocimetry, nonstress test, low-risk pregnancy. U Ultraso1111d Med 10:331, 1991)
MATERIALS AND METHODS After informed consent had been obtained, 1000 pa tients with low-risk pregnancies referred for antepar· tum monitoring were enrolled in this study. All had singleton gestations with certain ages assessed by early second-trimester ultrasonographic examination. Monthly prenatal visits excluded the presence of maternal and fetal complications. Each patient was considered only once for the study. The characteristics of the patients investigated are reported in Table 1. On the same day patients underwent both feta] heart rate monitoring in the form of nonstress test (NST) and Doppler flow-velocity waveform analyses. All the studies were carried out by prenatal nurses and a research fellow (A.S.). Fetal heart rates were recorded by means of a Hewlett Packard 8041 with an external ultrasound transducer while patients lay in a semirecumbent position. NST tracings were evaluated by Fischer score9 as well as by classification as reactive or d d h nonreactive. A reactive tracing was consi ere in t e presence of at least two fetal heart rate accelerations
© 1991 by the American Institute of Ultrasound in Medicine• J Ultrasound Med 10;331 - 335, 1991•0278-4297/ 91/$3.50
332
DOPPLER VELOCIMETRY VS NONSTRESS TEST
Table t : Characteristics of the Pregnancies Considered in this Study Ch11racteristic Age (yr) Parity Gestational age at NST a nd Doppler recordings (wk) Gestational age at delivery (wk) Interval between recordings and delivery (days) Birthweight (g)
C1."Sarean section fo r fetal distn.>ss Lite decelerations Repetitive variable decclemtions with onset before rupture of membranes Repetitive variable decelerations with onst?t after rupture of membranes Birthwl.'ight percentile
One thousand singleton low-risk pregnancies were cross-sectionally studied at 36- 40 weeks gestation with continuous+wave Doppler ultrasonography in order to assess its usefulness as an antepartum monitoring technique for the identification of fetuses at risk of developing an adverse outcome. Uterine artery and umbilical artery S/ D values were measured and related to fetal outcome. Results were compared with those of the nonstress test. No significant differences in fetal outcome, with the exception of birth weight, were found between patients with normal and abnormal uterine
A
bnormal velocity waveforms in the uterine and umbilical arteries seem to be associated with pregnancy complications such as hyperten sion, ' intrauterine growth retardation, 2 and fetal distress,1 and several studies have suggested a potential application of Doppler ultrasonography to predict ad verse outcome in high-risk pregnancies. 4" 6 Few data are available on the significance of Doppler velocimetry in the general population, and the results so far obtained are contradictory. 7•8 This study assesses the accuracy of Doppler velocimetry in the prediction of fetal distress and compares the validity of this technique with fetal heart rate monitoring in a low-risk population.
Received from the Laboratory of Fetal Physiology, Department of Obstetrics and Gynecology, Universita Cattolica s. Cuore, Rome; and "Department of Obstetrics and Gynecology,. Universila di Ancona, Ancona, Italy.. Address correspondence and reprint requests to Dr. Domenico Arduini: 1st Cl. Ostetrica e Ginecologica, Universita Cattolica Cuore, Largo A. Gemelli, 8, 00168 Roma, Italy.
s.
S/ D values. In pregnancies with abnormal umbilical S/ D values, a higher incidence of cesarean section for feta I distress and lower birth weight were observed. Moreover, those newborns more frequently had complications such as low 5-minute Apgar score, requiring resuscitation and admission to the intensive care unit. When compared to nonstress test, umbilical velocimetry showed a higher efficiency in identifying fetuses at risk for adverse outcome. KEY WORDS: antepartum monitoring, Doppler velocimetry, nonstress test, low-risk pregnancy. U Ultraso1111d Med 10:331, 1991)
MATERIALS AND METHODS After informed consent had been obtained, 1000 pa tients with low-risk pregnancies referred for antepar· tum monitoring were enrolled in this study. All had singleton gestations with certain ages assessed by early second-trimester ultrasonographic examination. Monthly prenatal visits excluded the presence of maternal and fetal complications. Each patient was considered only once for the study. The characteristics of the patients investigated are reported in Table 1. On the same day patients underwent both feta] heart rate monitoring in the form of nonstress test (NST) and Doppler flow-velocity waveform analyses. All the studies were carried out by prenatal nurses and a research fellow (A.S.). Fetal heart rates were recorded by means of a Hewlett Packard 8041 with an external ultrasound transducer while patients lay in a semirecumbent position. NST tracings were evaluated by Fischer score9 as well as by classification as reactive or d d h nonreactive. A reactive tracing was consi ere in t e presence of at least two fetal heart rate accelerations
© 1991 by the American Institute of Ultrasound in Medicine• J Ultrasound Med 10;331 - 335, 1991•0278-4297/ 91/$3.50
332
DOPPLER VELOCIMETRY VS NONSTRESS TEST
Table t : Characteristics of the Pregnancies Considered in this Study Ch11racteristic Age (yr) Parity Gestational age at NST a nd Doppler recordings (wk) Gestational age at delivery (wk) Interval between recordings and delivery (days) Birthweight (g)
C1."Sarean section fo r fetal distn.>ss Lite decelerations Repetitive variable decclemtions with onset before rupture of membranes Repetitive variable decelerations with onst?t after rupture of membranes Birthwl.'ight percentile
