Time-velocity waveforms of sonograms obtained by pulsed Doppler ultrasound from the umbilical artery were analysed in the fetuses of 75 pregnant women.
A total of 75 examinations were carried out from the 35th to 43th weeks of pregnancy. The ratio of peak systolic(A) to end-diastolic (B) flow velocity(A/B ratio), pulsatility index(PI) and resistance index (RI) were measured as an index of
placental
vascular resistance
The neonates were divided in three groups based on their percentile birth weight: <10%, 10 % to 75%, and >75% for the gestational age. In the lower birth weight groups (<10%0, placental vascular resistance as reflected by the A/B ratio, or PI, or
RI was
significantly higher than that in the upper birth weight groups(p<0.05).
We calculated the predictive value of this test in identifying the growht-retarded fetus. A/B ratio, PI or RI value higher than the ncrmal mean value plus 2 SD of each index for the gestational age was defined as normal. The sensitivity,
specificity,
positive predictive value, negative predictive value were measured by A/B ratio, PI, RI, respectively.
We classified the populations into two groups(Group A; RIApgar
score and more frequent intrauterine fetal death.
These data suggests that the analysis of umbilical artery blood flow velocity waveforms may be useful in identifying growth-retarded fetuses and perinatal outcome.
|