Blood Flow Velocity Waveforms of the Umbilical Artery in a Normal Population: Reference Values from 18 Weeks to 42 Weeks of Gestation

F. Bahlmann; M. Fittschen; I. Reinhard; S. Wellek; A. Puhl

doi:10.1055/s-0031-1299294

Ultraschall in der Medizin - European Journal of Ultrasound, Table of Contents

Ultraschall Med 2012; 33(7): E80-E87
DOI: 10.1055/s-0031-1299294

Original Article

Blood Flow Velocity Waveforms of the Umbilical Artery in a Normal Population: Reference Values from 18 Weeks to 42 Weeks of Gestation

Dopplersonografische Referenzkurven von der A. umbilicalis in einer Normalpopulation zwischen 18 und 42 Schwangerschaftswochen

F. Bahlmann

¹Obstetrics and Gynecology, Bürgerhospital, Frankfurt

,

M. Fittschen

¹Obstetrics and Gynecology, Bürgerhospital, Frankfurt

,

I. Reinhard

²Division of Biostatistics, Central Institute of Mental Health, Mannheim

,

S. Wellek

³ZI Department for Biostatistics, University of Heidelberg, Mannheim

,

A. Puhl

⁴Obstetrics and Gynecology, University, Mainz

› Author Affiliations

Abstract

Purpose: The aim of the present study was to calculate new Doppler reference ranges for systolic, intensity-weighted mean, and end-diastolic blood flow velocities (V_max, V_mean, V_min) and fetal heart rate and impedance indices (PI, RI) of the umbilical artery by automatic waveform analysis.

Materials and Methods: A cross-sectional prospective study of 1926 low-risk pregnancies was performed at 18 – 42 weeks of gestation. The measurements were carried out in the region of a free floating loop of cord. Reference ranges for the individual measuring parameters were constructed based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle. The intraobserver reliability was also assessed.

Results: A significant increase in umbilical blood flow velocity was observed at 18 – 42 weeks of gestation (V_max = 33.7 cm/sec to 65 cm/sec (p < 0.001), V_mean = 18.2 cm/sec to 38.7 cm/sec (p < 0.001) and V_min = 8.2 to 31 cm/sec (p < 0.001). Reference curves for the pulsatility and the resistance index were associated with significant decreases with increasing gestational age (PI: 18 weeks: 1.3; 28 weeks: 1.1; 42 weeks: 0.8 and RI: 18 weeks: 0.7; 28 weeks: 0.6; 42 weeks: 0.5). The fetal heart rate decreased from 147 – 134 bpm. The intraobserver reliability was low, but of no clinical relevance.

Conclusion: The reference ranges for blood flow velocities and resistance indices in the umbilical artery calculated by the authors serve as the basis for Doppler ultrasound antenatal examinations in a normal patient population and enable the early diagnosis of fetal risk.

Zusammenfassung

Ziel: Die vorliegende Studie wurde mit dem Ziel durchgeführt, neue Normkurven für systolische, intensitätsgewichtete mittlere und enddiastolische Flussgeschwindigkeiten (V_max, V_mean, V_min), für die fetale Herzfrequenz und die Gefäßwiderstände (PI, RI) mithilfe einer automatisierten Hüllkurvenanalyse von der A. umbilicalis zu erstellen.

Material und Methoden: Eine prospektive Querschnittsstudie bei 1926 normalen Schwangerschaften wurde zwischen 18 – 42 Schwangerschaftswochen durchgeführt. Die Dopplermessungen wurden im Bereich einer freien Nabelschnurschlinge durchgeführt. Für die einzelnen Dopplerparameter der A. umbilicalis erfolgte die Konstruktion von Referenzbändern basierend auf einer Wachstumsfunktion einer 4-parametrischen Klasse monotoner Funktionen, die durch kleinste Quadrate-Anpassung bestimmt wird.

Ergebnisse: Ein signifikanter Anstieg der umbilikalen Blutflussgeschwindigkeiten wurde zwischen der 18. und 42. Schwangerschaftswoche beobachtet (V_max = 33,7 cm/s bis 65 cm/s (p < 0,001), V_mean = 18,2 cm/s bis 38,7 cm/s (p < 0,001) und V_min = 8,2 bis 31 cm/s (p < 0,001). Die Pulsatilitäts- und Resistenz-Indizes (PI, RI) zeigten mit zunehmendem Gestationsalter eine signifikante Abnahme (PI: 18 SSW: 1,3; 28 SSW: 1,1; 42 SSW: 0,8 und RI: 18 SSW: 0,7; 28 SSW: 0,6; 42 SSW: 0,5). Die fetale Herzfrequenz fiel von 147 auf 134 Spm (p < 0,001). Die Intraobserver-Reliabilität war niedrig und ohne statistische Relevanz.

Schlussfolgerung: Neue dopplersonografische Referenzkurven von den Blutflussgeschwindigkeiten der A. umbilicalis und den Widerstandsindizes (PI, RI) konnten an einem Normalkollektiv errechnet werden. Die vorliegenden Normkurven können als Referenzwerte für den frühzeitigen Nachweis einer fetalen Gefährdung herangezogen werden.

Key words

ultrasound color Doppler - fetus - umbilical artery - obstetrics - reference values

Full Text

References

References
1 Fitzgerald D, Drumm JE. Noninvasive measurement of the fetal circulation using ultrasound: a new method. BMJ 1977; 2: 1450-1451
2 Alfirevic Z, Neilson JP. Doppler ultrasonography in high-risk pregnancies: Systematic review with meta-analysis. Am J Obstet Gynecol 1995; 172: 1379-1387
3 Marsal K. Rational use of Doppler ultrasound in perinatal medicine. J Perinat Med 1994; 22: 463-474
4 Arabin B, Bergmann PL, Pachaly J et al. Percentile values of qualitative blood flow velocity waveforms of uteroplacental and fetal vessels. Ultraschall Klin Prax 1988; 3: 132-140
5 Hendricks SK, Sorensen TK, Wang KY et al. Doppler umbilical artery waveform indices – normal values from fourteen to forty-two weeks. Am J Obstet Gynecol 1989; 161: 761-765
6 Hüneke B, Holst A, Schröder HJ et al. Normal reference values for Doppler flow velocity wave form indices A/B-ratio, Resistance and Pulsatility index obtained from the uterine and umbilical arteries in uncomplicated pregnancies – a longitudinal study. Geburtsh u Frauenheilk 1995; 55: 616-622
7 Thompson RS, Trudinger BJ, Cook CM et al. Umbilical artery velocity waveforms: normal reference values for A/B ratio and Pourcelot ratio. Br J Obstet Gynaecol 1988; 95: 589-591
8 Trudinger BJ, Giles WB, Cook CM et al. Fetal umbilical artery flow velocity waveforms and placental resistance: clinical significance. Br J Obstet Gynaecol 1985; 92: 23-30
9 Arström K, Eliasson A, Hariede JH et al. Fetal blood velocity waveforms in normal pregnancies. Acta Obstet Gynecol Scand 1989; 68: 171-178
10 Ferrazzi E, Gementi P, Bellotti M et al. Doppler velocimetry: critical analysis of umbilical, cerebral and aortic reference values. Eur J Obstet Gynecol Reprod Biol 1990; 38: 189-196
11 Gudmundsson S, Marsal K. Umbilical artery and uteroplacental blood flow velocity waveforms in normal pregnancy: a cross sectional study. Acta Obstet Gynecol Scand 1988; 67: 347-354
12 Pearce JM, Campbell S, Cohen-Overbeek T et al. 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
13 Scherjon SA, Kok JH, Oosting H et al. Intra-observer and interobserver reliability of the pulsatility index calculated from pulsed Doppler flow velocity waveforms in three vessels. Br J Obstet Gynecol 1993; 100: 134-138
14 Acharya G, Wilsgaard T, Berntsen GKR et al. Reference ranges for serial measurements of umbilical artery Doppler indices in the second half of pregnancy. Am J Obstet Gynecol 2005b 192,937-944
15 Arduini D, Rizzo G. Normal values of pulsatility index from fetal vessels: a cross sectional study on 1556 healthy fetuses. J Perinat Med 1990; 18: 165-172
16 Bahlmann F, Wellek S, Reinhardt I et al. Reference values of ductus venosus flow velocities and calculated waveform indices. Prenat Diagn 2000; 20: 623-634
17 Bahlmann F, Wellek S, Reinhardt I et al. Reference values of fetal aortic flow velocity waveforms and associated intra-observer reliability in normal pregnancies. Ultrasound Obstet Gynecol 2001; 17: 42-49
18 Baschat AA, Gembruch U. The cerebroplacental Doppler Ratio revisited. Ultrasound Obstet Gynecol 2003; 21: 124-127
19 Kurmanavicius J, Florio I, Wisser J et al. Reference resistance indices of the umbilical, fetal middle cerebral and uterine arteries at 24-42 weeks of gestation. Ultrasound Obstet Gynecol 1997; 10: 112-120
20 Parra-Cordero M, Lees C, Missfeld-Lobos H et al. Fetal arterial and venous Doppler pulsatility index and time averaged velocity ranges. Prenat Diagn 2007; 27: 1251-1257
21 Altman DG, Chitty LS. Design and analysis of studies to derive charts of fetal size. Ultrasound Obstet Gynecol 1993; 3: 378-384
22 Altman DG, Chitty LS. Charts of fetal size: 1. Methodology. Br J Obstet Gynaecol 1994; 101: 29-34
23 Royston P, Altman DG. Design and analysis of longitudinal studies of fetal size. Ultrasound Obstet Gynecol 1995; 6: 307-312
24 Royston P, Wright EM. How to construct „normal ranges“ for fetal variables. Ultrasound Obstet Gynecol 1998; 11: 30-38
25 Bahlmann F, Merz E, Weber G et al. Transvaginal sonographic biometry in early pregnancy – a growth model. Ultraschall in Med 1997; 18: 196-204
26 Merz E, Wellek S. Normal fetal development profiles – a model to obtain standard development graphs for the head and abdominal parameters and the long limb bones. Ultraschall in Med 1996; 17: 153-162
27 Wellek S, Merz E. Age related reference ranges for growth parameters. Meth Inform Med 1995; 4: 523-528
28 Fleis JL. The design and analysis of clinical experiments. New York: John Wiley & Sons; 1986
29 Giles WB, Lingman G, Marsal K et al. Fetal volume blood flow and umbilical artery flow velocity waveform analysis: A comparison. Br J Obstet Gynaecol 1989; 93: 461-465
30 Ruissen CJ, van Vugt JMG, de Haan J. Variability of PI calculations. Eur J Obstet Gynecol Reprod Bio 1988; 27: 213-220
31 Mulders L, Muijsers G, Jongsma H et al. The umbilical artery blood flow velocity waveform in relation to fetal breathing movements, fetal heart rate and fetal behavioural states in normal pregnancy at 37 to 39 weeks. Early Hum Dev 1986; 14: 283-293
32 Reuwer PJHM, Bruinse HW, Stoutenbeek P et al. Doppler assessment of the fetoplacental circulation in normal and growth-retarded fetuses. Eur J Obstet Gynecol Reprod Biol 1984; 18: 199-205
33 Acharya G, Wilsgaard T, Berntsen GKR et al. Reference ranges for serial measurements of blood velocity and pulsatility index at the intra-abdominal portion, and fetal and placental ends of the umbilical artery. Ultrasound Obstet Gynecol 2005; 26: 162-169
34 Sonesson SE, Fouron JC, Drblik SP et al. Reference values for Doppler velocimetric indices from fetal an placental ends of the umbilical artery during normal pregnancy. J Clin Ultrasound 1993; 21: 317-324
35 Skoll MA, Fouron JC, Sonesson SE et al. Doppler velocimetric indices from the abdominal and placental ends of the umbilical artery of growth-restriced fetuses. J Clin Ultrasound 1997; 25: 421-424
36 Predanic M, Kolli J, Yousefzadeh P et al. Disparate blood flow patterns in parallel umbilical arteries. Obstet Gynecol 1998; 91: 757-760
37 Reece EA, Hagay Z, Assimakopoulos E et al. Diabetes mellitus in pregnancy and the assessment of umbilical artery waveforms using pulsed Dopler ultrasonography. J Ultrasound Med 1994; 13: 73-80
38 Salvesen DR, Higueras MT, Mansur CA et al. Placental and fetal Doppler velocimetry in pregnancies complicated by maternal diabetes mellitus. Am J Obstet Gynecol 1993; 168: 645-652
39 Zimmermann P, Kujansuu E, Tuimala R. Doppler velocimetry of the umbilical artery in pregnancies complicated by insulin-dependent diabetes mellitus. Eur J Obstet Gynecol Reprod Biol 1992; 47: 85-93
40 Fadda GM, Cherchi PL, D’Antona D et al. Umbilical artery pulsatility index in pregnancies complicated by insulin-dependent diabetes mellitus without hypertension. Gynecol Obstet Invest 2001; 51: 173-177
41 Pietryga M, Brazert J, Wender-Ozegowska E et al. Abnormal uterine Doppler is related to vasculopathy in pregestational diabetes mellitus. Circulation 2005; 112: 2496-2500
42 Owen P, Murphy J, Farrell T. Is there a relationship between estimated fetal weight and umbilical artery Doppler impedance indices?. Ultrasound Obstet Gynecol 2003; 22: 157-159
43 Khoury J, Haugen G, Tonstad S et al. Effect of a cholesterol-lowering diet during pregnancy on maternal and fetal Doppler velocimetry: the CARRDIP study. Am J Obstet Gynecol 2007; 196: 549.e-549.e7