Duplux Doppler sonograpby is an important diagnostic tool in modem obestetrices and its
contributions to the assessment of small for gestational age (SGA) foetus can no longer be
ignorred.
The middle cereberal artery (MCA) flow velocity waveforms were obtained in 16 normal
fetuses, the pulsatility index (PI) values of their MCA were higher at 25 to 30 weeks gestation
than those observed during the two periods of major cereberal cellular multiplication in the
human foetus (i.e 15-20 weeks and at end of gestation). The PI of the MCA was also deter
mined in 33 SGA fetuses. A middle cereberai artery PI value below our normal range was re
corded in 9 of the 33 smail-for-gestational age fetuses (27.3 %). These SGA fetuses with ab-
' normal PI value had a significantly higher incidence of abnormal foetal heart rate and was
admitted into the neonatal intensive care unit. There were 3 deaths in 9 of SGA fetuses
(33.3%) with abnormal low middle cereberal aretery PI, and 3 deaths In 24 small-forgestational
age fetuses (12.5 %) with normal MCA pulsatility index values. The PI sensitivi
ty and specificity; predictive validity for adverse perinatal outcome; calculated results are
67% and 84 % respectively.
Our data indicate that the PI of the MCA in the normal human foetus has a parabolic pat
tern between 15-20 weeks and at late in the third trimester of gestation. Also, the results sug
gest that the SGA fetuses with a normal middle cereberal artery PI is at lower risk than the fe
tuses with abnormal PI values. Moreover, management of SGA fetuses may be aided by the
study of their MCA waveforms. |
