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INTRAUTERINE GROWTH RESTRICTION |
Acta Obstet Gynecol Scand. 1996 Feb;75(2):113-9.
Accuracy of the umbilical arteries Doppler flow velocity waveforms in
detecting adverse perinatal outcomes in a high-risk population.
Todros T, Ronco G, Fianchino O, Rosso S, Gabrielli S, Valsecchi L, Spagnolo
D, Acanfora L, Biolcati M, Segnan N, Pilu G.
Istituto di Ginecologia e Ostetricia, Universita' di Torino, Italy.
Objectives:
To define the accuracy of the umbilical artery Doppler flow
velocity waveforms, according to different cut-off values, in predicting
adverse perinatal outcomes among fetuses at high risk of hypoxic
complications. SUBJECTS: Two hundred and sixty-five pregnant women with
diagnosis of small for gestational age fetus and/or pregnancy induced
hypertension studied in four Italian ultrasound units.
Methods:
Prospective
study. Serial Doppler ultrasound measurements of the umbilical artery were
performed. Results were not available for clinical management. Cut-off
curves, corresponding to different age-specific centiles of the pulsatility
index distribution among pregnancies resulting in healthy newborns,
regardless of birthweight, were computed by regression methods. Sensitivity,
specificity, positive predictive value and negative predictive value of such
cut-off curves, and of absent/reverse end-diastolic flow, in predicting
different adverse outcomes were estimated. The adverse outcomes were:
perinatal or neonatal death (OUTCOME 1). Death or Apgar<7 at 5' or need for
admission to intensive care unit or other hypoxic related abnormalities
(OUTCOME 2). Either OUTCOME 2 or birthweight<l0th centile (OUTCOME 3). Both
OUTCOME 2 and birthweight<10th centile (OUTCOME 4).
Results:
The best
accuracy was in predicting OUTCOMES 1 and 4. Positive predictive value
increased strongly with higher cut-off curves while negative predictive
value only decreased slightly. For absent/reverse end-diastolic flow,
negative predictive value and positive predictive value were respectively
94% and 39% for death, and 81% and 72% respectively for OUTCOME 2. For the
95th centile curve the corresponding figures were 96%, 33% and 84%, 67%. The
60th centile curve had a 85% and 74% sensitivity value for death and OUTCOME
2 respectively, but the corresponding positive predictive values were 18%
and 40% only.
Conclusions:
The findings of an absent end diastolic flow or
of pulsatility index values above the 95th centile curve strongly suggest it
is time to deliver the fetus. The 60th centile curve is the most suitable to
recognize fetuses at risk for abnormal outcome, but early delivery should be
avoided because of its low positive predictive value.
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