ABNORMAL UMBILICAL ARTERY WAVEFORMS

- NON-RANDOMIZED STUDIES

Several reports on the value of umbilical artery Doppler velocimetry as a screening test in both "low" and "high" risk pregnant women.

• The test appears to be inadequate for screening "low" risk groups (1,2).
• Sensitivity and specificity are low.
• 97-98 healthy women would be alarmed unnecessarily to detect two to three abnormal pregnancies (2).
• The use of doppler as a screening test in this group might need to be revisited if an effective early treatment for an abnormal fetoplacental circulation emerges in the future (3).
• The link between abnormal Doppler indices in the umbilical artery and abnormal perinatal outcome is much stronger in "high" risk women. This is especially true for absent or reversed end diastolic flow (high vascular resistance in the fetoplacental circulation).
• Sensitivity of absent end diastolic flow in predicting perinatal death = 67%.
• Specificity = 98%.
• There is an 80-fold increase risk of dying (95% confidence interval), when a fetus has absent end diastolic flow (4).
• Numerous smaller studies examining the relationship between abnormal Doppler results and perinatal outcome, suggest that adverse outcome is more frequent in fetuses with abnormal umbilical artery Doppler studies.
• Death (5-7).
• Permanent neurological damage (5).
• Intraventricular hemorrhage (6,8).
• Prolonged hospitalization (8).
• Low Apgar score (6).
• Abnormal metabolic status (9,10).
• There is a higher proportion of chromosomally abnormal fetuses with abnormal Doppler findings. Rizzo and co-workers (11) suggest that invasive antenatal blood sampling is only justified if: Absent end diastolic flow in the umbilical cord is accompanied by:
• Maternal age >35 years.
• Gestational age <27 weeks.
• Multiple malformations.
• No pre-eclampsia.

REFERENCES

1. Atkinson MW, Maher JE, Owen J et.al. The predictive value of umbilical artery Doppler studies for eclampsia or fetal growth retardation in a preeclampsia prevention trial. Obstet Gynecol 1994;83:609-612.
2. Todros T, Ferrazzi E, Arduini D, Bastonero S et.al. Performance of Doppler ultrasonography as a screening test in low risk pregnancies: results of a multicentre study. J Ultrasound Med 1995;14:343-348.
3. Alfirevic Z, Neilson JP. The current status of Doppler sonography in obstetrics. Current Opinion in Obstetrics and Gynecology 1996;8:114-118.
4. Thornton JG, Lilford RJ. Do we need randomized trial of antenatal test of fetal well-being? Br J Obstet Gynaecol 1993;100:197-200.
5. Valcamonico A, Danti L, Frusca T et.al. Absent end-diastolic velocity in umbilical artery: risk of neonatal morbidity and brain damage. Am J Obstet Gynecol 1994;170:796-801.
6. Yoon BH, Lee CM, Kim SW. An abnormal umbilical artery waveform: a strong and independent predictor of adverse perinatal outcome in patients with preeclampsia. Am J Obstet Gynecol 1994;171:713-721.
7. Poulain P, Palaric JC, Paris-Liado J et.al. Fetal umbilical doppler in a population of 541 high-risk pregnancies: prediction of perinatal mortality and morbidity. Eur J Obstet Gynecol Reprod Biol 1994;54:191-196.
8. Ganziano EP, Knox H, Ferrara B et.al. IS it time to reassess the risk for the growth-retarded fetus with normal doppler velocimetry of the umbilical artery? Am J Obstet Gynecol 1994;170:1734-1743.
9. Steiner H, Staudach A, Spitzer D et.al. Growth deficient fetuses with absent or reversed umbilical artery end-diastolic flow are metabolically compromised. Early Hum Dev 1995;41:1-9.
10. Donner C, Vermeylen D, Kirkpatrick C et.al. Management of the growth-restricted fetus: the role of non invasive tests and fetal blood sampling. Obstet Gynecol 1995;85:965-970.
11. Rizzo G, Pietropolli A, Capponi A et.al. Chromosomal abnormalities in fetuses with absent end-diastolic velocity in umbilical artery: analysis of risk factors for an abnormal karyotype. Am J Obstet Gynecol 1994;171:827-831.