Development of quantitative Doppler indices for uteroplacental and fetal blood flow during the third trimester

Copyright

ELSEVIER

Ultrasound in Med. & Biol., Vol. 22. No. 7. pp. 823-835. 19% 0 1996 World Federation for Ultrasound in Medicine & Biology Printed in the USA. All rights reserved 0301-5629/% $15.00 + .OO

PII: SO301-5629( 96)00090-7

aOriginal

Contribution

DEVELOPMENT OF QUANTITATIVE DOPPLER INDICES UTEROPLACENTAL AND FETAL BLOOD FLOW DURING THE THIRD TRIMESTER HENDRIK

FOR

JOEIW,+

ANDREAS FUNK,’ MARTIN GOETZ,+ HOLGER KUEHLWEIN,~ ALFRED KLEIN? and HEINRICH FENDEL* ‘Department of Obstetrics and Gynaecology, Technical University of Aachen, Germany; and *Heilig-Geist-Krankenhaus, Cologne, Germany (Received

6 November

1995; in jinal form

9 April

1996)

Abstract-The aim of our study was to describe the development of uteroplacental and fetal blood flow during the third trimester. Doppler examination was carried out on 393 uncomplicated pregnancieswith uncomplicated term delivery. Using a pulsedcolor Doppler, we calculated the maximum systolic, meanand maximum end-diastolic velocity after correcting the angle of insonation. Patients under tocolysis or other medication influencing blood flow parameters were excluded from thii cross-sectionalstudy. Summarizing the results gained by Doppler ultrasound investigation of the uteroplacental and fetal blood vessels,we created quantiles as quantitative Doppler indicesfor the maximum systolic, mean(TAMX = time averaged maximum velocity) and maximum end-diastolic velocity. The following conclusionscould be drawn: (1) resistanceto the blood flow in the maternal portion of the placenta does not change during the third trimester: (2) resistanceto the blood flow on the fetal side of the placenta decreasesup to week 42 of gestation; (3) cerebral vascular resistancedecreasesconstantly up to gestationalweek 42; and (4) vascular resistanceto the blood flow of the kidney decreasesonly slightly during the third trimester. Thii study offers clinically important values for quantitative Doppler flow velocimetry for the first time. We hope that our findings improve the usefulnessof Doppler ultrasound as a diagnostic tool in obstetrical management. Key Words: Doppler flow velocity waveform analysis,Quantitative Doppler indices,Obstetrical management, Pregnancy complication, Uteroplacental blood flow, Fetal blood flow.

INTRODUCTION

as the A/B ratio, resistance index (RI) or pulsatility index (PI), are primarily influenced by the end-diastolic velocity. Fetal blood velocity waveforms are characterized by very low end-diastolic velocities, so that small changes of end-diastolic velocity cause distinct changes in these qualitative Doppler indices (Arduini and Rizzo 1990; Fendel and Sohn 1989; Gudmundsson and Marsal 1988; Pearce et al. 1988). Quantitative Doppler values, such as the maximum systolic, mean and maximum end-diastolic velocity, are more difficult to obtain, as the examiner must position the angle between the Doppler beam and the blood vessel exactly (Gill 1985; Maulik et al. 1989). This may be one reason why quantitative Doppler values have been rarely used up to the present time to interpret Doppler flow patterns. The knowledge of absolute velocities can help to identify the pertinent blood vessel. Otherwise, it is possible that a measurement considered to denote the uterine artery in reality describes an arcuate or inferior epigastric artery, whereas a peripheral cerebral blood

Doppler ultrasound has become a widely established tool for obstetrical diagnosis over the last several years (Fendel and Sohn 1989; Schneider and Loos 1989; Trudinger et al. 1985). Its usefulness in the clinical management of high-risk pregnancies has been discussed controversially ( DeVore et al. 1987; Low 1991; Trudinger et al. 1991) . The role Doppler ultrasound may play detecting perinatal risks depends on the accuracy of the measurement and the skill of the examiner to interpret the Doppler results (Gill 1985; Maulik et al. 1989; Pearce et al. 1988). As far as we are aware, quantitative Doppler flow velocity waveform analysis has been rarely performed up to the present time (Thompson et al. 1985 ) . Normal values for quantitative Doppler testing have not yet been published. Routinely used Doppler indices, such Address correspondence to: Dr. Hendrik Joem, Department of Obstetrics and Gynecology, Technical University of Aachen, Tittardsfeld 104, 52072 Aachen, Germany. 823

824

Ultrasound in Medicine and Biology Table 1. Patient characteristics

(n = 393).

Mean A.Y (~1 Doppler examination (wk) Delivery (wk) Birth weight (g)

28.4 36.4 34F

SD 0.21 0.2 0.19 22

Range 16.8-45.8 28-42 38-42 2530-5030

vessel may mimic the middle cerebral artery. Knowledge of the maximum systolic velocity usually found in the uterine or middle cerebral arteries avoids misleading interpretation of Doppler measurements (Fende1 and Sohn 1989). The reduction of the maximum systolic velocity in these arteries is another indication of a pathologic blood flow pattern (Fendel and Sohn 1989). Examining the fetal descending aorta, Bilardo et al. (1990) found that the mean velocity correlates better with blood gas alteration caused by fetal distress than the qualitative Doppler indices using the Kranzbtihler 8130 duplex Doppler. Using solely qualitative indices for the interpretation of Doppler results reduces the amount of information available. Consequently, an erroneous discrepancy between Doppler results and clinical outcome may occur, In predicting pregnancy complications such as IUGR or fetal distress, qualitative Doppler indices seldom surpass 60% sensitivity and 90% specificity (Devoe et al. 1990; DeVore et al. 1987; Low 1991). It is the aim of this investigation to create quantiles for uteroplacental and fetal blood flow describing the development of peripheral vascular resistance during the third trimester. These quantiles enable the clinician to interpret Doppler results in an improved manner by using both qualitative and quantitative indices. The correlation between pregnancy outcome and Doppler

Table 2. Criteria for inclusion

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results should be closer and Doppler measurements more helpful than they are today. MATERIALS

AND METHODS

Patients From October 1991 to October 1993,853 patients were examined in our hospital using Doppler ultrasound. Patient characteristics are listed in Table 1. Only patients with uncomplicated pregnancy and term delivery of a healthy and mature newborn were included in this cross-sectional study. The gestational ages of these 393 patients ranged from 28 to 42 weeks, The gestational age was confirmed by known menstrual history and ultrasonic measurement during first or early second trimester. All pregnancies were singleton and only one measurement of each patient was recruited for the study. None of these patients had been given any medication that may have influenced blood flow, i.e., tocolytic drugs. All criteria for inclusion or exclusion of patients are given in Table 2. Doppler examination Doppler examination was performed in the previously described manner (Fendel and Sohn 1989). We investigated the right and left uterine artery, the umbilical artery, and the fetal middle cerebral and fetal renal arteries. We chose the uterine arteries to study the maternal portion of the placenta including the blood vessel system of the spiral arteries. The umbilical artery was considered to offer information covering the fetal side of the placenta including the blood vessels of the villi. In addition, we examined the fetal middle cerebral and renal arteries to obtain information about the fetal blood circulation, thus having examined an important cerebral and abdominal artery. Investigating these four arteries, it should be possible to judge the

or exclusion

of patients.

Inclusion criteria

Exclusion criteria

Singleton pregnancy Gestational age ascertained by menstrual history and ultrasonography No evidence of malformation No evidence of pregnancy complications

Multiple pregnancy Gestational age not ascertained Minor or major malformation Bleeding ex ufero premature labour premature rupture of membranes Bclampsia, preeclampsia, HELLP Intrauterine growth retardation Any tocolytic medication Preterm or postterm delivery Caesarean section Any signs of fetal distress (umbilical artery pH <7.2 or S-min Apgar score <8) Birthweight below 10th percentile Repeated Doppler examinations Doppler examination by any other author

No medication influencing blood flow Term delivery Vaginal delivery No evidence of fetal distress Birth weight above 10th percentile Doppler examination once during pregnancy Doppler examination by first author (HI.)

Development of quantitative Doppler indices 0 H. JOERN et al.

complete uteroplacental and fetal circulation and its hemodynamic changes. We did not examine the fetal descending aorta, because the angle between this blood vessel and the ultrasound beam usually exceeds 60”. Investigation was performed only by the author himself using an Acuson 128 color Doppler with a 3.5/5-MHz transducer. The high-pass filter was set at 125 Hz. Doppler recordings were taken from the uterine arteries at the level of their crossing under the external iliac vessels, examining the ascending branch near the cervix. The umbilical artery was investigated at a point equidistant from the abdominal and placental insertion. At least 2 cm of the cord were required to be visible on the screen in direction to the transducer, without any kinking of the umbilical-blood vessels. The middle cerebral artery was investigated at the level of the greater wings of the sphenoid, and the renal artery in the vicinity of its branching from the abdominal aorta. The vessel was first localized with real-time ultrasound. After correcting the ultrasound beam to minimize the angle of insonation, the sample volume was completely placed over the vessel. In the absence of fetal breathing and fetal movements, the blood flow pattern over five consecutive and uniform heart cycles was recorded. To describe the flow pattern characteristics, we calculated the maximum systolic, mean, and maximum end-diastolic velocities of the aforementioned arteries. In our study, “mean” velocity is calculated by the mean value of the maximum frequency shift during one cardiac cycle (TAMX = time averaged maximum velocity). We calculated the mean of the right and left uterine artery to obtain one value describing “the uterine artery.” The angle between the Doppler beam and the blood vessel ranged from 40” to 60” examining the uterine arteries and from 0” to 30” examining all other blood vessels. Recordings that did not comply with these conditions were excluded from our study. The intra- and interobserver variabilities were not calculated in this study, because all pregnancies were only investigated once by the first author (H.J.). The intraobserver variability known from other studies in our hospital is 4.7%, 5.3%, 5.9% and 6.1% in regard to the uterine, umbilical, middle cerebral and renal arteries, respectively (unpublished data).

Statistics We generated the lOth, 5Oth, and 90th quantile using Microsoft Excel 5.0 on a 386 personal computer (Microsoft Corp., Redmond, WA). Data were collected by examining “the uterine artery” in 364 cases, the umbilical artery being recorded 362 times. In addition, the middle cerebral and renal arteries were examined in 326 and 301 cases, respectively. p Values were

825

calculated for all quantiles to determine whether or not a decrease or increase of any quantile was significant. RESULTS Figure 1 illustrates the typical distribution Doppler measurements had in regard to the gestational age at examination. For demonstration purposes, the results of the umbilical artery are shown. The other arteries possess a similar distribution pattern. Characterizing the quantiles, we investigated whether the increase or decrease of each velocity during the third trimester was significant. A change of velocity was considered significant when p < 0.05 was attained. Uterine artery The quantiles of the uterine artery for the previously specified velocities are shown in Fig. 2. The three velocities increase only slightly. All quantiles of these three velocities remain nearly parallel to each other during the third trimester. The 90th quantile of each velocity increases to a greater extent than does the 5Oth, with the 10th quantile of each velocity increasing the least. Only the increase demonstrated by the 50th quantile of the mean velocity reached our level of significance, as did the 50th and 90th quantiles of the maximum end-diastolic velocity. Maximum systolic velocity (V-) ranges between 108 cm/s (10th quantile) and 189 cm/s (90th quantile) during week 28 and between 110 cm/s (10th quantile) and 210 cm/s (90th quantile) during week 42 of gestation. Mean velocity (V,,) ranges between 69 cm/s (10th quantile) and 128 cm/s (90th quantile) during week 28 and from 74 cm/s (10th quantile) to 149 cm/ s (90th quantile) during week 42. Maximum end-diastolic velocity (V,,) ranges between 50 cm/s ( 10th quantile) and 96 cm/s (90th quantile) and from 56 cm/s ( 10th quantile) to 120 cm/ s (90th quantile) during weeks 28 and 42, respectively. Umbilical artery By investigating the umbilical artery, we were able to demonstrate two effects (Fig. 3) : (a) the quantiles pertaining to this artery show greater upward inclination during the third trimester than do those of the uterine artery; (b) the increase of each 50th quantile is greater than that of the 9Oth, with the rise of the 10th quantiles being even greater still. This effect is most obvious for the maximum systolic velocity and somewhat less for the mean velocity. For the maximum end-diastolic velocity, the increase is only slight. The 10th and 50th quantiles of the maximum systolic velocity and 10th quantile of the mean velocity failed to reach our level of significance.

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40 35 30 25 = 20 15 IO 5 0 26

28

30

32

34

36

38

40

42

44

week of gestation

Fig. 1. Gestational week, distribution of Doppler measurements (abscissa: week of gestation; ordinate: IZ= number of Doppler measurements). Maximum systolic velocity ranges between 36 cm/s ( 10th quantile) and 51 cm/s (90th quantile) during week 28 and between 32 cm/s ( 10th quantile) and 69 cm/s (90th quantile) during week 42 of gestation. Mean velocity ranges between 21 cm/s (10th quantile) and 33 cm/s (90th quantile) during week 28 and from 22 cm/s ( 10th quantile) to 46 cm/s (90th quantile) during week 42. Maximum end-diastolic velocity ranges between 9 cm/s ( 10th quantile) and 18 cm/s (90th quantile) and from 13 cm/s ( 10th quantile) to 30 cm/s (90th quantile) during weeks 28 and 42, respectively. Middle cerebral artery

Figure 4 shows the quantiles created from the data for the fetal middle cerebral artery. Here the same development as for the umbilical artery could be demonstrated, The 90th quantiles of all velocities rise to a greater extent than do the SOth, with the 10th quantiles rising least. This effect was more obvious for the maximum end-diastolic velocity, slightly less for the mean velocity, with the maximum systolic velocity rising the least. The 10th quantile of the maximum end-diastolic velocity remains the same during the third trimester. Only the 10th quantile of the maximum systolic velocity missed our level of significance. Maximum systolic velocity ranges between 31 cm/s (10th quantile) and 57 cm/s (90th quantile) during week 28 and between 31 cm/s ( 10th quantile) and 78 cm/s (90th quantile) during week 42 of gestation. Mean velocity ranges between 11 cm/s (10th quantile) and 20 cm/s (90th quantile) during week 28 and from 17 cm/s (10th quantile) to 43 cm/s (90th quantile) during the week 42.

Maximum end-diastolic velocity ranges between 1 cm/s ( 10th quautile) and 3 cm/s (90th quantile) and from 7 cm/s ( 10th quantile) to 23 cm/s (90th quantile) during weeks 28 and 42, respectively.

Renal artery

The quantiles for the fetal renal artery develop in an inverse manner (Fig. 5). The quantiles of the maximum end-diastolic velocity rose to a greater extent than did the quantiles of the mean velocity, with the quantiles of the maximum systolic velocity remaining the same during the third trimester. The quantiles of each velocity remain parallel to each other. The 10th quantile of the maximum end-diastolic velocity lies below zero between gestational weeks 28 and 31. The 10th and 50th quautile of the maximum end-diastolic velocity reached our level of significance. Maximum systolic velocity ranges between 36 cm/s ( 10th quantile) and 68 cm/s (90th quantile) during week 28 and between 33 cm/s (10th quantile) and 69 cm/s (90th quantile) during week 42 of gestation. Mean velocity ranges between 12 cm/s (10th quantile) and 23 cm/s (90th quantile) during week 28 and from 13 cm/s ( 10th quantile) to 27 cm/s (90th quantile) during week 42. Maximum end-diastolic velocity ranges between -1 cm/s ( 10th quantile) and 5 cm/s (90th quantile) and from 3 cm/s (10th quantile) to 9 cm/s (90th quantile) during weeks 28 and 42, respectively. Tables containing the values characterizing 19 quantiles of the velocities of each artery are shown in the Appendix.

Developmentof quantitative Doppler indices0 H. JOERN

827

et al.

v tams(mla)

V min

(mls)

0.9 46 0.7 0.6 0.J 44 * week

of gestation

Fig. 2. The lOth, 5Oth, and 90th quantile of the maximum systolic ( Vm,, top), mean (V,, end-diastolic velocity (V,,,,,, bottom) of the uterine artery.

DISCUSSION Knowledge concerning the development and maturation of the placental and fetal circulation is fundamental to understanding the development of uteroplacental and fetal blood flow as it can be measured by Doppler ultrasound. The vascular development of the maternal portion of the placenta is nearly complete between gestational weeks 22 and 24, at which time the second trophoblastic invasion has occurred (Brosens et al. 1977; Robertson et al. 1975). After termination of this process, there is no qualitative change in placental vascular

, middle) and maximum

development, but only quantitative growth. Accordingly, blood flow velocities of the uterine arteries do not increase as much as blood flow velocities of the umbilical artery. All quantiles of all three velocities of the uterine artery develop nearly identically. As a result of our findings, we can surmise that resistance to the blood flow in the maternal portion of the placenta does not change during the third trimester. Blood flow velocities of the umbilical artery increase relatively and absolutely to a greater extent than do those of the uterine arteries. As the placenta matures, the short, thick, early stem villi branch repeatedly, forming progressively finer subdivisions and greater numbers of increas-

828

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Volume 22, Number 7, 1996

v mkl

Fig. 3. The 10th 5Oth, and 90th quantile of the maximum systolic (V,, , top), mean (VW, middle) and maximum end-diastolic velocity (Vti,, bottom) of the umbilical artery.

ingly small villi (Becker 1972; Benirschke and Kaufmann 1990; Giles et al. 1985). Capillary branching continues, especially under the conditions of hypoxia, modulated by certain placental hormones (Kaufmann et al. 1993). This development may continue until late third trimester. Accordingly, our quantiles calculated for the maximum enddiastolic velocity increase to a relatively gmater extent than do the quantiles calculated for the maximum systolic velocity. Again, we can surmise that resistance to the blood flow on the fetal side of the placenta decreases up to the week 42 of gestation. From animal models, we know that 80% of the aortic blood pressure is needed to guarantee sufficient placental perfusion (Dawes 1962). The remaining 20% guarantees sufficient blood flow to the fetal organs. With advancing pregnancy, this relation surely changes, with there being an increasing demand for

blood pressure to guarantee sufficient perfusion of the growing fetal organs. The maximum end-diastolic velocity of the fetal middle cerebral artery increases to a relatively greater extent than does the maximum systolic velocity. Cerebral vascular resistance seems to decrease constantly up to gestational week 42. Examining the fetal renal artery, we found a small increase in mean and a greater increase in maximum end-diastolic velocity, the maximum systolic velocity showing a very slight decrease. Because of the maturating renal circulation and the constant presence of enddiastolic velocities from the middle of the third trimester onward, the range of values narrows. It seems that vascular resistance to the blood flow of the kidney remains constant or decreases only very slightly during the third trimester.

Development of quantitative Doppler indices l H.

JOERN

et al.

829

(mls)

II

I I;

iiiiiiiiiiiiiiw1

I[/ / i I I I I I i I

v PiIl

Fig. 4. The lOth, 5Otb,and90th quantileof the maximumsystolic(V,, , top), mean(V,, , middle) andmaximum end-diastolicvelocity (V,,, bottom) of the fetal middle cerebralartery.

These findings may he explained by the progressive maturation of the blood vessels in these organs, leading to a decline in vascular resistance, which influences quantitative Doppler indices more than the increasing cardiac contmctility. To decide whether uteroplacental or fetal blood flow is normal or abnormal, many investigators use “cut-off ” poiuts or mean values and their standard deviations (Arduini and R.&o 1990; Fendel et al. 1990, Gudmundsson and Marsal 1988; Malcus et al. 1991; Trudinger et al. 1985). The use of a “cut-off” point entails having only one numerical value to judge an intricate and developing phenomenon such as the maturating blood vessel system of the placenta or the fetus. Use of a mean value with standard deviation may better reflect the phenomenon, but the data must be normally distributed. We consider the use of quantiles to be the best manner in which to characterize the

blood flow of the placenta and fetus. A comparison of our quantitative Doppler values to normal values of other investigators was not possible, as no data could be gleaned from an analysis of recent literature. As is known from prior studies, qualitative Doppler indices such as the A/B ratio, t&stance index (RI), or pulsatihty index (PI) cannot predict perinatal risks in a manner sufficient to make Doppler ultrasound examination feasible as a screening tool in pregnancy (Low 1991). Recently, Doppler studies with animal models have shown that hypoxemia is only poorly elucidated using the afm mentioned qualitative indices as blood flow parameters (Cope1 et al. 1991; Schmidt et al. 1991; Malcus et al. 1991; Richardson et al. 1994; Rybakowski et al. 1994). Doppler velocimetty offers a vast amount of information as a basis for all the aforementioned parameters, qualitative as well as quantitative. The ratios A/B, RI and PI

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Ultrasound in Medicine and Biology

V mm (m/s)

0.71 0.70 0.0, 0.m 0.9 0.93 0.4, o.ro q,r 0.10 I

20

10

II

11

,1

Volume 22, Number 7, 1996

Y

,s

Y

n

Jo

,o

40

II

42

0.m OPJ 0.X0

v (0-1 (ds) *,n

Fig. 5. The lOth, 50th and 90th quantile of the maximum systolic (V,,,, , top), mean (V,, , middle) and maximum end-diastolic velocity (V,,, below) of the fetal renal artery. are composed of absolute velocities. The physiological and clinical relevance of both parameter types must be the same. In a prior publication, we could demonstrate that the sensitivity and specitkity in detecting certain pathological entities were higher when using the quantitative indices presented here (Joem et al. 1994). We hope that the usefulness of Doppler ultrasound examinations in obstetrical management may be improved using quantitative as well as qualitative indices. We do not want to abandon one index for another. Further studies are necessary to evaluate the clinical significance of all Doppler indices and show whether one index is better than another, or which, if not a combination of parameters, offers the most useful information for the clinician. REFERENCES Arduini D, Rizzo G. Normal values of pulsatility index from fetal vessels: a cross-sectional study on 1556 healthy fetuses. J Perinat Med 18 1990; 18:165-172.

Becker V. Pathologisch-anatomische Aspekte zur Plazentainsuffizienz. 2. Geburtsh Perinat 1972; 176:349-355. Benirschke K, Kaufmann P. Pathology of the human placenta. Berlin: Springer-Verlag, 1990. Bilardo CM, Nicolaides KH, Campbell S. Doppler measurements of fetal and uteroplacental circulations: Relationship with umbilical venous blood gas measured at cordocentesis. Am J Obstet Gyneco1 1990;162:115-120. Brosens I, Dixon HG, Robertson WB. Fetal growth retardation and the arteries of the placental bed. Br J Obstet Gynaecol 1977;84:656-663. Cope1 JA, Woudstra BR, Wentworth R, et al. Hypoxia cannot be detected by the umbilical S/D ratio in fetal lambs. J Matern Fetal Invest 1991;1:219-221. Dawes GS. The umbilical circulation. Am J Obstet Gynecol 1962;84:1634-1648. Devoe LD, Gardner P, Dear C, Castillo R. The diagnostic values of concurrent nonstress testing, amniotic fluid measurement, and Doppler velocimetry in screening a general high-risk population. Am J Obstet Gynecol 1990; 163:1040-1048. Devote GR, Brar HS, Platt LD. Doppler ultrasound in the fetus: A review of current applications. J Clin Ultrasound 1987; 15:687703.

Development of quantitative Doppler indices 0 H. Fendel H, Sohn C. Dopplersonographie in der Geburtshilfe. Berlin: Springer-Verlag, 1989. Fendel H, Fendel M, Jam H, Funk A, Doeker B, Meyers W. Dopplerscore zur Beurteilung des perinatalen Risikos. Ultraschall Klin Prax 1990;5:68-73. Giles WB, Ttudinger BJ, Baird PJ. Fetal umbilical artery flow velocity waveforms and placental resistance: Pathologic correlation. Br J Obstet Gynaecol 1985;92:31-38. Gill RW. Measurement of blood flow by ultrasound: Accuracy and sources of error. Ultrasound Med Biol 1985; 11:625-641. Gudmundsson S, Marsal K. Umbilical artery and uteroplacental blood flow velocity waveforms in normal pregnancy-A crosssectional study. Acta Obstet Gynecol Stand 1988;67:347-354. Joem H, Funk A, Kuehlwein H, Klein A. Doppler-Ultraschalluntersuchungen des venijsen Rtickflusses in pracardialen Venen beim Feten in normalen und gestorten Schwangerschaften. Z Geburtsh Perinat 1994; 198: l-6. Kaufmann P, Kohnen G, Kosanke G. Wechselwirkungen zwischen Plazentamorphologie und fetaler Sauerstoffversorgung. Gyn%kologe 1993;26:16-23. Low JA. The current status of maternal and fetal blood flow velocimetry. Am J Obstet Gynecol 1991; 164:1049-1063. Malcus P, Gudmundsson S, Marsal K, Kwok HH, Vengadasalam D, Ratnam SS. Umbilical artery Doppler velocimetry as a labor admission test. Obstet Gynecol 1991;77: lo- 16. Malcus P, Hiikegard K-H, Kjellmer I, Lingman G, Mama1 K, Rosen KG. The relationship between arterial blood velocity waveforms and acid-Base status in the fetal lamb during acute experimental asphyxia. J Matem Fetal Invest 1991; 1:29-34. Maulik D, Yarlagadda AP, Youngblood JP, Willoughby L. Components of variability of umbilical arterial Doppler velocimetryA prospective analysis. Am J Obstet Gynecol 1989: 160:14061412. Pearce JM, Campbell S, Cohen-Overbeek T, Hackett G, Hemandez J, Royston JP. References ranges and sources of variation for indices of pulsed Doppler flow velocity waveforms from the uteroplacental and fetal circulation. Br J Obstet Gynaecol 1988;95:248-256.

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et al.

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Richardson B, Connors G, Carmichael L, Homan J. Cerebral waveform indices of the ovine fetus with changes in behavioural activity. J Matem Fetal Invest 1994;4:S9. Robertson WB, Brosens I, Dixon G. Uteroplacental vascular pathology. Eur J Obstet Gynecol Reprod Biol 1975;5:47-65. Rybakowski C, Holm G, Htineke B, Cetin E, Schrijder H. Assessment of Doppler indices as indicator of peripheral resistence in fetal sheep. J Matem Fetal Invest 1994;4:S 11. Schmidt KG, DiTommaso M, Silverman NH, Rudolph AM. Evaluation of changes in umbilical blood flow in the fetal lamb by Doppler waveform analysis. Am J Obstet Gynecol 1991; 164:1118-1126. Schneider KTM, Loos W. 10 Jahre geburtshilfliche Dopplersonographie-Entwicklung und Perspektiven. Geburtsh Frauenheilk 1989; 49:407-415. Thompson RS, Trudinger BJ, Cook CM. Doppler ultrasound waveforms in the fetal umbilical artery: Quantitative analysis technique. Ultrasound Med Biol 1985; 11:707-718. Trudinger BJ, Giles WB, Cook CM, Bombardieri J, Collins L. Fetal umbilical artery flow velocity waveforms and placental resistance: Clinical significance. Br J Obstet Gynaecol 1985;92:2330. Trudinger BJ, Giles WB, Cook CM. Uteroplacental blood flow velocity-Time waveforms in normal and complicated pregnancy. Br J Obstet Gynaecol 1985;92:39-45. Trudinger BJ, Cook CM, Giles WB, Ng S, Fong E, Conelly A, Wilcox W. Fetal umbilical artery velocity waveforms and subsequent neonatal outcome. Br J Obstet Gynaecol 1991:98:378384.

APPENDIX Tables Al-Al2 show the values for the lst, 3rd, 5th, 7th, lOth, 2Oth, 25th, 3Oth, 4Oth, 5Oth, 6Oth, 70th. 75th, 8Oth, 9Oth, 93rd, 95th. 97th and 99th quantiles of the maximum systolic, mean and maximum end-diastolic velocity calculated using data derived from Doppler measurements of the uterine, umbilical, fetal middle cerebral and renal arteries during the third trimester.

Table Al. Values of quantilesof the maximumsystolic velocity of the uterine artery (m/s) calculatedusingDoppler data. 5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

ssw

1st

3rd

28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

0.931 0.928 0.925 0.922 0.919 0.915

0.983 0.981 0.979 0.976 0.974 0.971

1.039 1.065 1.077 1.171 1.184 1.205 1.269 1.405 1.490 1.622 1.747 1.818 1.886 1.927 1.955 2.012 2.068 1.036 1.063 1.079 1.177 1.195 1.218 1.284 1.413 1.501 1.627 1.745 1.817 1.901 1.947 1.978 2.038 2.104 1.033 1.062 1.080 1.184 1.206 1.232 1.298 1.421 1.512 1.632 1.743 1.817 1.916 1.967 2.001 2.065 2.141

0.912

0.969

1.021

1.055

1.086

1.211

1.249

1.287

1.358

1.454

1.558

1.654

1.734

1.817

1.978

2.048

2.092

2.171

2.287

0.909 0.906 0.903 0.900 0.896 0.893 0.890 0.887

0.966 0.964 0.962 0.959 0.957 0.954 0.952 0.949

1.018 1.015 1.011 1.008 1.005 1.002 0.999 0.996

1.053 1.051 1.049 1.048 1.046 1.044 1.042 1.040

1.087 1.089 1.090 1.091 1.093 1.094 1.096 1.097

1.218 1.225 1.231 1.238 1.245 1.252 1.259 1.265

1.260 1.271 1.282 1.293 1.303 1.314 1.325 1.336

1.301 1.314 1.328 1.342 1.355 1.369 1.383 1.396

1.372 1.387 1.402 1.417 1.431 1.446 1.461 1.476

1.462 1.470 1.478 1.486 1.494 1.503 1.511 1.519

1.569 1.580 1.592 1.603 1.614 1.626 1.637 1.648

1.649 1.665 1.670 1.675 1.681 1.686 1.692 1.697

1.732 1.730 1.728 1.725 1.723 1.721 1.719 1.717

1.817 1.817 1.817 1.816 1.816 1.816 1.816 1.816

1.993 2.009 2.024 2.040 2.055 2.070 2.086 2.101

2.069 2.089 2.109 2.130 2.150 2.170 2.191 2.211

2.115 2.137 2.160 2.183 2.206 2.228 2.251 2.274

2.198 2.225 2.251 2.278 2.305 2.331 2.358 2.384

2.323 2.360 2.397 2.433 2.470 2.506 2.543 2.579

1.030

1.060

1.081

1.191

1.217

1.246

1.313

1.429

1.524

1.638

1.741

1.817

1.932

1.987

2.024

2.092

2.177

1.027 1.058 1.083 1.198 1.228 1.260 1.328 1.437 1.535 1.643 1.739 1.817 1.947 2.008 2.046 2.118 2.214 1.024 1.056 1.084 1.204 1.239 1.273 1.343 1.446 1.546 1.649 1.736 1.817 1.963 2.028 2.069 2.145 2.250

832

Ultrasound

in Medicine

and Biology

Volume

22, Number

7, 1996

Table A2. Values of quantiles of the mean velocity of the uterine artery (m/s) calculated using Doppler data. ssw 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

0.570 0.568 0.567 0.565 0.563 0.561 0.559 0.557 0.555 0.553 0.551 0.549 0.547 0.545 0.544

0.615 0.615 0.615 0.615 0.615 0.614 0.614 0.614 0.614 0.614 0.614 0.614 0.614 0.614 0.614

0.655 0.656 0.656 0.656 0.656 0.657 0.657 0.657 0.657 0.658 0.658 0.658 0.658 0.658 0.659

0.672 0.673 0.674 0.676 0.677 0.678 0.680 0.681 0.683 0.684 0.685 0.687 0.688 0.689 0.691

0.693 0.697 0.700 0.703 0.706 0.709 0.712 0.716 0.719 0.722 0.725 0.728 0.731 0.734 0.738

0.743 0.749 0.755 0.762 0.768 0.774 0.781 0.787 0.793 0.800 0.806 0.813 0.819 0.825 0.832

0.767 0.776 0.784 0.792 0.800 0.808 0.817 0.825 0.833 0.841 0.849 0.858 0.866 0.874 0.882

0.774 0.786 0.799 0.811 0.824 0.836 0.849 0.862 0.874 0.887 0.899 0.912 0.924 0.937 0.949

0.831 0.843 0.855 0.867 0.879 0.891 0.903 0.915 0.927 0.99 0.951 0.963 0.975 0.987 0.999

0.918 0.928 0.939 0.949 0.960 0.970 0.981 0.991 1.002 1.012 1.023 1.033 1.044 1.054 1.064

1.021 1.028 1.034 1.041 1.048 1.055 1.061 1.068 1.075 1.081 1.088 1.095 1.101 1.108 1.115

1.066 1.073 1.080 1.087 1.095 1.102 1.109 1.116 1.123 1.130 1.137 1.144 1.151 1.159 1.166

1.117 1.124 1.131 1.138 1.145 1.152 1.159 1.166 1.173 1.180 1.187 1.194 1.201 1.209 1.216

1.152 1.162 1.173 1.184 1.194 1.205 1.215 1.226 1.236 1.247 1.257 1.268 1.279 1.289 1.300

1.278 1.293 1.308 1.323 1.338 1.353 1.368 1.383 1.398 1.413 1.428 1.444 1.459 1.474 1.489

1.291 1.311 1.331 1.350 1.370 1.390 1.409 1.429 1.449 1.468 1.488 1.508 1.527 1.547 1.567

1.313 1.335 1.357 1.379 1.401 1.423 1.445 1.467 1.489 1.511 1.533 1.555 1.578 1.600 1.622

1.344 1.370 1.396 1.422 1.448 1.474 1.500 1.526 1.552 1.578 1.604 1.630 1.656 1.682 1.708

1.377 1.409 1.441 1.473 1.504 1.536 1.568 1.600 1.632 1.663 1.695 1.727 1.759 1.791 1.822

Table A3. Values of quantiles of the maximum end-diastolic velocity of the uterine artery (m/s) calculated using Doppler data. ssw 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

0.445 0.439 0.433 0.428 0.422 0.416 0.411 0.405 0.399 0.394 0.388 0.382 0.377 0.371 0.365

0.472 0.469 0.466 0.463 0.460 0.457 0.454 0.451 0.449 0.446 0.443 0.440 0.437 0.434 0.431

0.493 0.493 0.492 0.491 0.491 0.490 0.489 0.489 0.488 0.487 0.487 0.486 0.485 0.484 0.484

0.499 0.501 0.502 0.504 0.505 0.507 0.508 0.510 0.511 0.513 0.514 0.516 0.517 0.519 0.520

0.503 0.507 0.511 0.515 0.519 0.523 0.527 0.531 0.535 0.539 0.543 0.547 0.551 0.555 0.559

0.555 0.561 0.568 0.575 0.582 0.588 0.595 0.602 0.609 0.616 0.622 0.629 0.636 0.643 0.649

0.571 0.579 0.588 0.597 0.605 0.614 0.623 0.631 0.640 0.649 0.657 0.666 0.675 0.683 0.692

0.580 0.591 0.602 0.613 0.625 0.636 0.647 0.658 0.669 0.681 0.692 0.703 0.714 0.726 0.737

0.624 0.636 0.648 0.661 0.673 0.686 0.698 0.710 0.723 0.735 0.748 0.760 0.773 0.785 0.797

0.674 0.687 0.701 0.714 0.728 0.741 0.755 0.768 0.782 0.795 0.809 0.822 0.835 0.849 0.862

0.730 0.743 0.757 0.770 0.784 0.797 0.811 0.824 0.838 0.851 0.865 0.878 0.892 0.905 0.919

0.793 0.805 0.818 0.831 0.843 0.856 0.868 0.881 0.894 0.906 0.919 0.932 0.944 0.957 0.969

0.843 0.854 0.866 0.877 0.888 0.900 0.911 0.922 0.934 0.945 0.956 0.968 0.979 0.990 1.002

0.889 0.901 0.913 0.925 0.937 0.949 0.961 0.973 0.986 0.998 1.010 1.022 1.034 1.046 1.058

0.957 0.974 0.992 1.009 1.026 1.044 1.061 1.078 1.096 1.113 1.131 1.148 1.165 1.183 1.200

0.978 0.999 1.020 1.041 1.062 1.084 1.105 1.126 1.147 1.168 1.189 1.210 1.232 1.253 1.274

1.008 1.031 1.054 1.077 1.100 1.123 1.146 1.169 1.192 1.215 1.238 1.260 1.283 1.306 1.329

1.057 1.081 1.106 1.131 1.155 1.180 1.205 1.230 1.254 1.279 1.304 1.328 1.353 1.378 1.402

1.106 1.132 1.159 1.186 1.213 1.240 1.267 1.293 1.320 1.347 1.374 1.401 1.428 1.454 1.481

Table A4. Values of quantiles of the maximum systolic velocity of the umbilical artery (m/s) calculated using Doppler data. ssw 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

0.303 0.292 0.281 0.270 0.259 0.249 0.238 0.227 0.216 0.205 0.194 0.183 0.172 0.161 0.151

0.333 0.323 0.312 0.302 0.291 0.281 0.271 0.260 0.250 0.240 0.229 0.219 0.208 0.198 0.188

0.352 0.344 0.335 0.327 0.319 0.310 0.302 0.293 0.285 0.276 0.268 0.259 0.251 0.243 0.234

0.350 0.345 0.340 0.335 0.331 0.326 0.321 0.316 0.311 0.307 0.302 0.297 0.292 0.287 0.282

0.355 0.352 0.350 0.348 0.345 0.343 0.341 0.339 0.336 0.334 0.332 0.329 0.327 0.325 0.322

0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375

0.382 0.383 0.384 0.384 0.385 0.386 0.387 0.387 0.388 0.389 0.390 0.390 0.391 0.392 0.393

0.395 0.396 0.397 0.397 0.398 0.399 0.400 0.400 0.401 0.402 0.402 0.403 0.404 0.404 0.405

0.412 0.416 0.419 0.422 0.426 0.429 0.433 0.436 0.439 0.443 0.446 0.450 0.453 0.456 0.460

0.437 0.440 0.443 0.446 0.449 0.452 0.454 0.457 0.460 0.463 0.466 0.469 0.472 0.474 0.477

0.441 0.447 0.454 0.461 0.467 0.474 0.480 0.487 0.493 0.500 0.507 0.513 0.520 0.526 0.533

0.464 0.471 0.478 0.485 0.492 0.499 0.506 0.512 0.519 0.526 0.533 0.540 0.547 0.554 0.560

0.470 0.478 0.487 0.495 0.504 0.512 0.521 0.529 0.537 0.546 0.554 0.563 0.571 0.580 0.588

0.479 0.489 0.498 0.508 0.518 0.527 0.537 0.547 0.556 0.566 0.576 0.585 0.595 0.605 0.614

0.512 0.524 0.536 0.549 0.561 0.573 0.586 0.598 0.611 0.623 0.635 0.648 0.660 0.672 0.685

0.518 0.532 0.546 0.560 0.573 0.587 0.601 0.615 0.628 0.642 0.656 0.670 0.683 0.697 0.711

0.522 0.537 0.552 0.567 0.582 0.598 0.613 0.628 0.643 0.658 0.674 0.689 0.704 0.719 0.734

0.523 0.541 0.558 0.576 0.593 0.611 0.629 0.646 0.664 0.681 0.699 0.716 0.734 0.752 0.769

0.515 0.539 0.562 0.586 0.609 0.632 0.656 0.679 0.703 0.726 0.750 0.773 0.797 0.820 0.844

Development

of quantitative

Doppler

indices

833

0 H. JOERN et al.

Table A5. Values of quantiles of the mean velocity of the umbilical artery (m/s) calculated using Doppler data. ssw

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

0.180 0.174 0.168 0.162 0.157 0.151 0.145 0.139 0.133 0.127 0.121 0.115 0.109 0.104 0.098

0.200 0.194 0.187 0.181 0.175 0.169 0.163 0.157 0.150 0.144 0.138 0.132 0.126 0.120 0.114

0.211 0.207 0.202 0.197 0.192 0.188 0.183 0.178 0.173 0.169 0.164 0.159 0.154 0.150 0.145

0.209 0.207 0.205 0.203 0.201 0.199 0.197 0.194 0.192 0.190 0.188 0.186 0.184 0.182 0.180

0.213 0.213 0.214 0.214 0.214 0.214 0.214 0.214 0.214 0.214 0.215 0.215 0.215 0.215 0.215

0.236 0.237 0.237 0.238 0.239 0.239 0.240 0.240 0.241 0.242 0.242 0.243 0.244 0.244 0.245

0.241 0.242 0.243 0.245 0.246 0.247 0.248 0.249 0.250 0.251 0.252 0.253 0.255 0.256 0.257

0.245 0.247 0.250 0.253 0.255 0.258 0.261 0.263 0.266 0.268 0.271 0.274 0.276 0.279 0.282

0.257 0.261 0.265 0.268 0.272 0.276 0.279 0.283 0.287 0.291 0.294 0.298 0.302 0.305 0.309

0.268 0.272 0.277 0.282 0.286 0.291 0.296 0.300 0.305 0.310 0.314 0.319 0.324 0.328 0.333

0.279 0.285 0.290 0.295 0.301 0.306 0.312 0.317 0.322 0.328 0.333 0.338 0.344 0.349 0.355

0.292 0.299 0.306 0.313 0.319 0.326 0.333 0.340 0.347 0.354 0.361 0.368 0.375 0.382 0.389

0.301 0.309 0.316 0.323 0.331 0.338 0.346 0.353 0.361 0.368 0.376 0.383 0.391 0.398 0.406

0.313 0.321 0.328 0.335 0.342 0.349 0.357 0.364 0.371 0.378 0.385 0.392 0.400 0.407 0.414

0.329 0.339 0.348 0.358 0.367 0.377 0.387 0.396 0.406 0.415 0.425 0.435 0.444 0.454 0.463

0.339 0.349 0.359 0.369 0.379 0.388 0.398 0.408 0.418 0.428 0.438 0.448 0.458 0.468 0.477

0.344 0.355 0.366 0.377 0.388 0.399 0.411 0.422 0.433 0.444 0.455 0.466 0.477 0.488 0.499

0.348 0.361 0.374 0.387 0.400 0.413 0.426 0.439 0.452 0.465 0.478 0.491 0.504 0.518 0.531

0.346 0.364 0.382 0.400 0.418 0.436 0.454 0.472 0.490 0.508 0.526 0.544 0.562 0.580 0.598

Table A6. Values of quantiles of the maximum end-diastolic velocity of the umbilical artery (m/s) calculated using Doppler data. SW 28 29 30 31 32 33 34 35 36 37 ii 40 41 42

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

0.074 0.073 0.073 0.072 0.072 0.072 0.071 0.071 0.070 0.070 0.070 0.069 0.069 0.068 0.068

0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.080

0.085 0.085 0.086 0.087 0.088 0.089 0.090 0.091 0.092 0.093 0.094 0.095 0.096 0.097 0.098

0.086 0.088 0.090 0.092 0.094 0.096 0.099 0.101 0.103 0.105 0.107 0.109 0.111 0.113 0.115

0.090 0.093 0.097 0.100 0.103 0.106 0.109 0.112 0.115 0.118 0.121 0.124 0.127 0.130 0.133

0.096 0.101 0.106 0.111 0.117 0.122 0.127 0.133 0.138 0.143 0.148 0.154 0.159 0.164 0.170

0.098 0.104 0.110 0.115 0.121 0.126 0.132 0.138 0.143 0.149 0.154 0.160 0.166 0.171 0.177

0.103 0.109 0.115 0.121 0.126 0.132 0.138 0.144 0.150 0.156 0.161 0.167 0.173 0.179 0.185

0.113 0.120 0.127 0.133 0.140 0.147 0.153 0.160 0.167 0.174 0.180 0.187 0.194 0.200 0.207

0.119 0.127 0.134 0.141 0.148 0.156 0.163 0.170 0.177 0.184 0.192 0.199 0.206 0.213 0.221

0.131 0.138 0.146 0.153 0.160 0.168 0.175 0.183 0.190 0.197 0.205 0.212 0.220 0.227 0.234

0.144 0.152 0.160 0.167 0.175 0.182 0.190 0.197 0.205 0.212 0.220 0.227 0.235 0.242 0.250

0.150 0.158 0.166 0.175 0.183 0.191 0.199 0.207 0.216 0.224 0.232 0.240 0.248 0.257 0.265

0.161 0.169 0.177 0.185 0.193 0.201 0.209 0.217 0.225 0.233 0.241 0.249 0.256 0.264 0.272

0.183 0.191 0.199 0.207 0.215 0.223 0.231 0.240 0.248 0.256 0.264 0.272 0.280 0.288 0.296

0.185 0.194 0.204 0.213 0.222 0.232 0.241 0.250 0.260 0.269 0.278 0.288 0.297 0.306 0.316

0.185 0.197 0.208 0.219 0.230 0.241 0.252 0.263 0.274 0.285 0.296 0.307 0.318 0.330 0.341

0.192 0.205 0.218 0.230 0.243 0.256 0.269 0.282 0.295 0.307 0.320 0.333 0.346 0.359 0.371

0.198 0.214 0.230 0.246 0.262 0.277 0.293 0.309 0.325 0.341 0.357 0.373 0.389 0.405 0.421

Table A7. Values of quantiles of the maximum systolic velocity of the fetal middle cerebral artery (m/s) calculated using Doppler data. ssw

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

0.237 0.234 0.232 0.230 0.228 0.226 0.223 0.221 0.219 0.217 0.215 0.212 0.210 0.208 0.206

0.256 0.254 0.252 0.249 0.247 0.245 0.243 0.241 0.239 0.237 0.235 0.232 0.230 0.228 0.226

0.273 0.271 0.269 0.268 0.266 0.264 0.262 0.260 0.258 0.256 0.254 0.253 0.251 0.249 0.247

0.287 0.286 0.285 0.284 0.282 0.281 0.280 0.279 0.277 0.276 0.275 0.274 0.272 0.271 0.270

0.311 0.310 0.310 0.309 0.309 0.309 0.308 0.308 0.307 0.307 0.306 0.306 0.306 0.305 0.305

0.372 0.375 0.378 0.381 0.384 0.388 0.391 0.394 0.397 0.401 0.404 0.407 0.410 0.413 0.417

0.381 0.385 0.389 0.393 0.397 0.401 0.405 0.409 0.413 0.417 0.421 0.425 0.429 0.433 0.437

0.386 0.393 0.400 0.407 0.415 0.422 0.429 0.437 0.444 0.451 0.458 0.466 0.473 0.480 0.487

0.415 0.424 0.433 0.442 0.451 0.461 0.470 0.479 0.488 0.497 0.506 0.515 0.524 0.533 0.543

0.424 0.436 0.449 0.462 0.475 0.487 0.500 0.513 0.526 0.539 0.551 0.564 0.577 0.590 0.602

0.449 0.463 0.476 0.490 0.504 0.518 0.531 0.545 0.559 0.573 0.586 0.600 0.614 0.627 0.641

0.488 0.500 0.513 0.525 0.538 0.550 0.563 0.575 0.588 0.600 0.613 0.625 0.638 0.650 0.663

0.507 0.520 0.532 0.545 0.557 0.570 0.582 0.595 0.608 0.620 0.633 0.645 0.658 0.670 0.683

0.523 0.537 0.551 0.566 0.580 0.594 0.608 0.623 0.637 0.651 0.665 0.680 0.694 0.708 0.722

0.565 0.580 0.596 0.611 0.627 0.642 0.658 0.673 0.689 0.704 0.720 0.735 0.751 0.766 0.782

0.572 0.590 0.607 0.624 0.642 0.659 0.676 0.693 0.711 0.728 0.745 0.763 0.780 0.797 0.815

0.577 0.596 0.615 0.634 0.653 0.672 0.691 0.710 0.729 0.748 0.767 0.786 0.805 0.824 0.843

0.584 0.606 0.628 0.651 0.673 0.6% 0.718 0.740 0.763 0.785 0.807 0.830 0.852 0.874 0.897

0.594 0.620 0.646 0.671 0.697 0.723 0.748 0.774 0.800 0.825 0.851 0.877 0.902 0.928 0.954

834 Table ssw 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

Ultrasound A8.

Values

1st 0.102 0.102 0.103 0.103 0.103 0.103 0.103 0.103 0.103 0.103 0.104 0.104 0.104 0.104 0.104

28 29 30 31 32 33 34 35 36 37 38 z 41 42

and Biology

velocity

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

0.106 0.107 0.107 0.108 0.108 0.109 0.109 0.110 0.110 0.111 0.111 0.112 0.112 0.113 0.113

0.109 0.110 0.111 0.112 0.113 0.115 0.116 0.117 0.118 0.120 0.121 0.122 0.123 0.125 0.126

0.110 0.113 0.116 0.118 0.121 0.124 0.126 0.129 0.132 0.134 0.137 0.140 0.142 0.145 0.148

0.114 0.118 0.122 0.127 0.131 0.135 0.140 0.144 0.148 0.153 0.157 0.161 0.166 0.170 0.174

0.126 0.132 0.138 0.145 0.151 0.158 0.164 0.170 0.177 0.183 0.189 0.196 0.202 0.208 0.215

0.127 0.135 0.143 0.150 0.158 0.165 0.173 0.181 0.188 0.196 0.204 0.211 0.219 0.226 0.234

0.131 0.140 0.149 0.159 0.168 0.177 0.187 0.196 0.205 0.215 0.224 0.234 0.243 0.252 0.262

0.143 0.152 0.162 0.172 0.181 0.191 0.201 0.211 0.220 0.230 0.240 0.250 0.259 0.269 0.279

0.154 0.164 0.173 0.183 0.193 0.203 0.213 0.222 0.232 0.242 0.252 0.262 0.271 0.281 0.291

0.156 0.168 0.180 0.192 0.205 0.217 0.229 0.241 0.254 0.266 0.278 0.290 0.303 0.315 0.327

A9.

Values middle

of the fetal

28 29 30 31 32 33 34 35 36 i;: 39 40 41 42

middle

22, Number

of the mean

cerebral

7, 1996

artery

(m/s)

calculated

using

Doppler

data.

70th

75th

80th

90th

93rd

95th

97th

99th

0.175 0.188 0.201 0.213 0.226 0.239 0.251 0.264 0.277 0.289 0.302 0.314 0.327 0.340 0.352

0.181 0.194 0.207 0.220 0.233 0.246 0.259 0.272 0.284 0.297 0.310 0.323 0.336 0.349 0.362

0.186 0.200 0.214 0.227 0.241 0.255 0.269 0.282 0.296 0.310 0.323 0.337 0.351 0.364 0.378

0.201 0.217 0.234 0.250 0.266 0.282 0.299 0.315 0.331 0.348 0.364 0.380 0.396 0.413 0.429

0.208 0.226 0.243 0.261 0.278 0.296 0.314 0.331 0.349 0.367 0.384 0.402 0.419 0.437 0.455

0.212 0.231 0.250 0.268 0.287 0.306 0.325 0.344 0.363 0.382 0.400 0.419 0.438 0.457 0.476

0.210 0.232 0.254 0.276 0.298 0.320 0.342 0.364 0.386 0.407 0.429 0.451 0.473 0.495 0.517

0.208 0.233 0.258 0.283 0.308 0.333 0.358 0.383 0.407 0.432 0.457 0.482 0.507 0.532 0.557

of quantiles of the maximum end-diastolic velocity of the fetal cerebral artery (m/s) calculated using Doppler data.

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

0.002 0.004 0.007 0.010 0.012 0.015 0.018 0.020 0.023 0.025 0.028 0.031 0.033 0.036 0.039

0.002 0.005 0.008 0.011 0.015 0.018 0.021 0.025 0.028 0.031 0.035 0.038 0.041 0.044 0.048

0.002 0.006 0.009 0.013 0.017 0.021 0.025 0.029 0.033 0.037 0.040 0.044 0.048 0.052 0.056

0.004 0.008 0.012 0.016 0.020 0.024 0.028 0.032 0.037 0.041 0.045 0.049 0.053 0.057 0.061

0.009 0.013 0.017 0.022 0.026 0.030 0.035 0.039 0.044 0.048 0.052 0.057 0.061 0.065 0.070

0.012 0.017 0.023 0.029 0.035 0.041 0.046 0.052 0.058 0.064 0.070 0.076 0.081 0.087 0.093

0.012 0.019 0.026 0.032 0.039 0.046 0.052 0.059 0.066 0.073 0.079 0.086 0.093 0.100 0.106

0.014 0.021 0.028 0.035 0.042 0.049 0.056 0.063 0.071 0.078 0.085 0.092 0.099 0.106 0.113

0.020 0.027 0.034 0.042 0.049 0.057 0.064 0.071 0.079 0.086 0.094 0.101 0.108 0.116 0.123

0.019 0.027 0.036 0.044 0.053 0.061 0.070 0.078 0.087 0.095 0.104 0.112 0.121 0.129 0.138

0.022 0.032 0.042 0.051 0.061 0.071 0.080 0.090 0.100 0.110 0.119 0.129 0.139 0.148 0.158

0.022 0.032 0.043 0.054 0.065 0.076 0.087 0.098 0.109 0.120 0.131 0.141 0.152 0.163 0.174

0.025 0.036 0.048 0.059 0.070 0.082 0.093 0.105 0.116 0.128 0.139 0.150 0.162 0.173 0.185

0.030 0.042 0.054 0.066 0.078 0.090 0.102 0.115 0.127 0.139 0.151 0.163 0.175 0.187 0.199

0.034 0.048 0.061 0.075 0.089 0.103 0.117 0.131 0.145 0.159 0.173 0.186 0.200 0.214 0.228

0.043 0.057 0.072 0.086 0.100 0.115 0.129 0.144 0.158 0.173 0.187 0.202 0.216 0.231 0.245

0.046 0.062 0.077 0.093 0.109 0.125 0.140 0.156 0.172 0.188 0.203 0.219 0.235 0.251 0.266

0.045 0.064 0.083 0.102 0.121 0.140 0.158 0.177 0.196 0.215 0.234 0.253 0.271 0.290 0.309

0.046 0.068 0.090 0.112 0.134 0.156 0.178 0.200 0.222 0.244 0.266 0.288 0.309 0.331 0.353

Table AlO. Values of quantiles of the fetal renal artery (m/s) ssw

Volume

of quantiles

Table

ssw

in Medicine

of the maximum calculated using

systolic Doppler

velocity data.

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

0.309 0.307 0.305 0.303 0.301 0.298 0.296 0.294 0.292 0.290 0.287 0.285 0.283 0.281 0.279

0.320 0.318 0.316 0.314 0.312 0.310 0.308 0.306 0.304 0.302 0.300 0.298 0.296 0.294 0.292

0.331 0.329 0.327 0.325 0.323 0.321 0.319 0.317 0.315 0.313 0.311 0.309 0.307 0.306 0.304

0.343 0.341 0.339 0.337 0.335 0.333 0.331 0.329 0.327 0.325 0.323 0.321 0.319 0.317 0.315

0.359 0.357 0.355 0.353 0.351 0.349 0.347 0.345 0.343 0.341 0.340 0.338 0.336 0.334 0.332

0.393 0.392 0.392 0.391 0.391 0.390 0.389 0.389 0.388 0.388 0.387 0.387 0.386 0.386 0.385

0.412 0.411 0.411 0.411 0.411 0.411 0.410 0.410 0.410 0.410 0.410 0.409 0.409 0.409 0.409

0.437 0.436 0.436 0.435 0.434 0.433 0.433 0.432 0.431 0.430 0.429 0.429 0.428 0.427 0.426

0.470 0.470 0.470 0.470 0.469 0.469 0.469 0.469 0.469 0.469 0.468 0.468 0.468 0.468 0.468

0.507 0.507 0.506 0.506 0.506 0.506 0.506 0.505 0.505 0.505 0.505 0.504 0.504 0.504 0.504

0.550 0.548 0.547 0.546 0.544 0.543 0.542 0.540 0.539 0.538 0.536 0.535 0.534 0.533 0.531

0.577 0.576 0.576 0.575 0.575 0.574 0.574 0.573 0.573 0.572 0.572 0.571 0.571 0.570 0.570

0.591 0.591 0.591 0.591 0.591 0.592 0.592 0.592 0.592 0.593 0.593 0.593 0.593 0.504 0.594

0.610 0.610 0.611 0.611 0.612 0.613 0.613 0.614 0.614 0.615 0.616 0.616 0.617 0.618 0.618

0.681 0.682 0.683 0.683 0.684 0.684 0.685 0.686 0.686 0.687 0.687 0.688 0.688 0.689 0.690

0.724 0.723 0.723 0.722 0.722 0.721 0.721 0.720 0.720 0.719 0.719 0.718 0.718 0.717 0.717

0.785 0.782 0.779 0.775 0.772 0.769 0.765 0.762 0.759 0.755 0.752 0.749 0.745 0.742 0.739

0.847 0.842 0.837 0.833 0.828 0.823 0.819 0.814 0.809 0.804 0.800 0.795 0.790 0.786 0.781

0.908 0.902 0.897 0.891 0.886 0.880 0.875 0.870 0.864 0.859 0.853 0.848 0.842 0.837 0.831

Development

Table Al 1. Values of qua&es ssw 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

1st 0.110 0.109 0.109 0.109 0.109 0.109 0.109 0.109 0.108 0.108 0.108 0.108 0.108 0.108 0.108

of quantitative

Doppler

indices

0 H. JOERN et al.

835

of the mean velocity of the fetal renal artery (m/s) calculated using Doppler data.

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.112 0.113

0.115 0.115 0.116 0.116 0.116 0.116 0.116 0.117 0.117 0.117 0.117 0.117 0.118 0.118 0.118

0.119 0.120 0.120 0.120 0.121 0.121 0.121 0.122 0.122 0.123 0.123 0.123 0.124 0.124 0.125

0.124 0.124 0.125 0.126 0.126 0.127 0.128 0.128 0.129 0.129 0.130 0.131 0.131 0.132 0.133

0.139 0.140 0.141 0.142 0.143 0.144 0.145 0.146 0.147 0,148 0.149 0.150 0.151 0.152 0.153

0.144 0.145 0.146 0.147 0.148 0.149 0.150 0.151 0.152 0.154 0.155 0.156 0.157 0.158 0.159

0.146 0.148 0.150 0.151 0.153 0.155 0.157 0.159 0.161 0.162 0.164 0.166 0.168 0.170 0.172

0.155 0.158 0.161 0.163 0.166 0.169 0.171 0.174 0.177 0.180 0.182 0.185 0.188 0.190 0.193

0.170 0.172 0.175 0.177 0.180 0.182 0.185 0.187 0.189 0.192 0.194 0.197 0.199 0.202 0.204

0.182 0.185 0.187 0.190 0.192 0.195 0.197 0.200 0.203 0.205 0.208 0.210 0.213 0.215 0.218

0.188 0.191 0.194 0.197 0.200 0.203 0.206 0.209 0.212 0.216 0.219 0.222 0.225 0.228 0.231

0.195 0.198 0.201 0.204 0.207 0.210 0.213 0.216 0.219 0.222 0.225 0.228 0.231 0.234 0.237

0.206 0.209 0.212 0.215 0.218 0.221 0.224 0.227 0.230 0.233 0.237 0.240 0.243 0.246 0.249

0.229 0.232 0.235 0.238 0.241 0.244 0.246 0.249 0.252 0.255 0.258 0.261 0.264 0.267 0.270

0.257 0.259 0.260 0.261 0.262 0.263 0.265 0.266 0.267 0.268 0.270 0.271 0.272 0.273 0.274

0.309 0.306 0.303 0.301 0.298 0.295 0.293 0.290 0.287 0.284 0.282 0.279 0.276 0.274 0.271

0.361 0.354 0.348 0.342 0.335 0.329 0.322 0.316 0.310 0.303 0.297 0.291 0.284 0.278 0.271

0.412 0.402 0.392 0.382 0.372 0.362 0.353 0.343 0.333 0.323 0.313 0.303 0.293 0.283 0.273

Table A12. Values of quantiles of the maximum end-diastolic velocity of the fetal renal artery (m/s) calculated using Doppler data. ssw

1st

3rd

5th

7th

10th

20th

25th

30th

40th

50th

60th

70th

75th

80th

90th

93rd

95th

97th

99th

28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

-0.011 -0.010 -0.008 -0.006 -0.005 -0.003 -0.001 0.000 0.002 0.004 0.005 0.007 0.008 0.010 0.012

-0.010 -0.008 -0.006 -0.004 -0.002 -0.000 0.002 0.003 0.005 0.007 0.009 0.011 0.013 0.015 0.017

-0.009 -0.007 -0.004 -0.002 0.000 0.003 0.005 0.007 0.009 0.012 0.014 0.016 0.019 0.021 0.023

-0.009 -0.006 -0.004 -0.001 0.001 0.004 0.007 0.009 0.012 0.014 0.017 0.019 0.022 0.025 0.027

-0.010 -0.007 -0.004 -0.001 0.002 0.004 0.007 0.010 0.013 0.016 0.019 0.021 0.024 0.027 0.030

-0.002 0.000 0.003 0.006 0.009 0.012 0.015 0.018 0.020 0.023 0.026 0.029 0.032 0.035 0.038

-0.001 0.002 0.005 0.008 0.011 0.014 0.017 0.020 0.023 0.026 0.029 0.032 0.035 0.038 0.041

0.000 0.003 0.006 0.010 0.013 0.016 0.019 0.022 0.025 0.028 0.032 0.035 0.038 0.041 0.044

0.007 0.010 0.013 0.016 0.019 0.021 0.024 0.027 0.030 0.033 0.036 0.039 0.042 0.045 0.048

0.011 0.014 0.017 0.020 0.023 0.026 0.029 0.032 0.035 0.038 0.041 0.044 0.047 0.050 0.054

0.014 0.017 0.020 0.024 0.027 0.031 0.034 0.037 0.041 0,044 0.047 0.051 0.054 0.057 0.061

0.016 0.020 0.023 0.027 0.031 0.035 0.039 0.043 0.046 0.050 0.054 0.058 0.062 0.066 0.069

0.015 0.020 0.024 0.029 0.033 0.038 0.043 0.047 0.052 0.056 0.061 0.065 0.070 0.075 0.079

0.017 0.022 0.027 0.032 0.037 0.042 0.047 0.052 0.057 0.062 0.067 0.072 0.077 0.082 0.087

0.046 0.049 0.052 0.055 0.058 0.061 0.064 0.068 0.071 0.074 0.077 0.080 0.083 0.086 0.089

0.068 0.070 0.071 0.072 0.074 0.075 0.076 0.078 0.079 0.081 0.082 0.083 0.085 0.086 0.087

0.104 0.102 0.101 0.099 0.098 0.096 0.095 0.093 0.092 0.090 0.089 0.087 0.086 0.085 0.083

0.140 0.136 0.132 0.127 0.123 0.119 0.114 0.110 0.106 0.101 0.097 0.093 0.088 0.084 0.079

0.177 0.170 0.163 0.155 0.148 0.141 0.134 0.126 0.119 0.112 0.105 0.097 0.090 0.083 0.076