A. Kurjak et S. Kupesic, PARALLEL DOPPLER ASSESSMENT OF YOLK-SAC AND INTERVILLOUS CIRCULATION IN NORMAL-PREGNANCY AND MISSED ABORTION, Placenta (Eastbourne), 19(8), 1998, pp. 619-623
This study assessed yolk sac morphology and vascularity and intervillo
us blood flow in normal early pregnancy and missed abortion. Transvagi
nal colour and pulsed Doppler were used in a prospective analysis of 8
7 normal pregnancies and 48 missed abortions between 6 and 12 weeks ge
station. The Kruskal-Wallis rank test was used to calculate the differ
ence in yolk sac diameter and vascularity visualization rate between g
estational weeks. Repeated measures analysis of variance was used for
comparison of the intervillous circulation between groups. The growth
of the yell; sac was considered statistically significant between gest
ational weeks 6 and 9, being most prominent between 9 and 10 weeks of
gestation. Vascularity of the yolk sac, characterized by low velocity
and absence of diastolic flow, was demonstrated in 67 per cent of norm
al pregnancies. Yolk sac blood flow was detected in 19 per cent of the
patients with missed abortion. Doppler analysis of the intervillous c
irculation demonstrated decreased peak velocity of the continuous flow
in patients with missed abortion for gestational weeks 11 and 12. It
is concluded that progressive decrease of yolk sac vascularity coincid
es with visualization of more prominent colour-coded areas within the
intervillous space. In patients with missed abortion, such changes do
not occur. (C) 1998 W. B. Saunders Company Ltd.