The aim of this work was to study the blood flow velocity waveforms
of the fetal umbilical and middle cerebral arteries as well as the umbilical
to middle cerebral Doppler ratio in post-terra pregnancies in order to assess
their validity in prediction of adverse perinatal outcome and to compare
their predictive values with that of amniotic fluid Index (All), modified
biophysical profile (BPP) and non stress test (NS7).
A prospective study of 80 pregnant women with 41 or more weeks of
gestation having singleton fetuses with no medical or obstetric complications.
All cases were evaluated by Duplex Doppler ultrasonography to
measure the pulsatility index (P1) of umbilical and middle cerebral arteries
from which U/ C arterial Doppler ratio was calculated. Also, ultrasound
assessment of API. modified BPP and NST were evaluated twice weekly.
Adverse perinatal outcome was defined as the occurrence offetal distress
(repetitive variable or late intrapartum decelerations), low Apgar score
(<7) at 5 minutes, umbilical artery pH < 7.25, admission to N1CU and or
perinatal death.
Twenty four of the studied 80 women (30%) had adverse perinatal outcome
and they had signcantly higher umbilical artery PI and U/ C ratio
(P< 0.05 & P < 0.01) and significantly lower middle cerebral artery PI (P <
0.05) than the group with normal perinatal outcome. The U/ C ratio was
more accurate parameter in the prediction of abnormal perinatal outcome
compared to the other studied parameters (sensitivity = 84%, specificity =
87.2%, positive predictive value = 75% negative predictive value = 92.3%
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and accuracy = 86.3%). These values were found to be more predictive
when. AFT was combined with PI U/C ratio.
Conclusion : Estimation of umbilical to middle cerebral arterial Doppler
PI ratio in uncomplicated post term pregnancies provides a more reliable
method for prediction of perinatal outcome when compared with AFL
mod Wed BPP and NSF. Combining PI U/C ratio with AFT provides more
accurate method for prediction of adverse perinatal outcome in post-term
pregnancies. |
