Preeclampsia

Ultrasound Obstet Gynecol 2008; 31: 310–313
Published online 4 February 2008 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.5252

Prediction of pre-eclampsia by uterine artery Doppler
imaging: relationship to gestational age at delivery and
small-for-gestational age
C. K. H. YU, O. KHOURI, N. ONWUDIWE, Y. SPILIOPOULOS and K. H. NICOLAIDES for The
Fetal MedicineFoundation Second-Trimester Screening Group
Harris Birthright Research Centre for Fetal Medicine, King’s College Hospital Medical School, London, UK

K E Y W O R D S: Doppler; pre-eclampsia; screening; small-for-gestational age

ABSTRACT

INTRODUCTION

Objectives To determine the relationship between preeclampsia, small-for-gestational age (SGA) and gestational age at delivery, and the effectof this relationship on
the prediction of pre-eclampsia by uterine artery Doppler
imaging.

Pre-eclampsia is a heterogeneous disorder with variable
maternal and fetal manifestations. Although the diagnosis of the condition relies on the demonstration of
hypertension and proteinuria in the mother, the clinical
outcome depends primarily on the presence of multisystem dysfunction in themother and impairment of growth
and oxygenation in the fetus. There is evidence that the
severity of the fetal compromise is mainly related to the
gestational age at the onset of pre-eclampsia. Thus, pathological studies have shown that the prevalence of placental
lesions in women with pre-eclampsia is inversely related to
the gestational age at delivery1,2 . Furthermore, epidemiological studieshave reported that preterm pre-eclampsia is
associated with low birth weight, whereas the birth weight
is often normal or increased in term pre-eclampsia3 – 6 .
Doppler ultrasound studies of the uterine arteries have
demonstrated that the clinical manifestations of preeclampsia are preceded by evidence of impaired placental
perfusion7,8 . A multicenter prospective screening study
usinguterine artery Doppler ultrasound imaging at
22–24 weeks of gestation in about 8000 singleton
pregnancies showed that the sensitivity for pre-eclampsia
with small-for-gestational age (SGA) is substantially
higher than that for pre-eclampsia without SGA (69%
versus 24%)9 . Furthermore, a study of more than
30 000 pregnancies showed that the pulsatility index
(PI) was above the 95th centile in78% of those that
subsequently developed pre-eclampsia requiring delivery
before 34 weeks, compared with 32% for late preeclampsia10 .
In this study we explore further the interrelation
between pre-eclampsia, SGA and gestational age at
delivery, and the effect of this relationship on the

Methods This was a multicenter prospective Doppler
study of the uterine artery at 22–24 weeks ofgestation in
unselected women with singleton pregnancies.
Results In the 30 639 pregnancies examined, the median
uterine artery pulsatility index (PI) was 1.0 and the 95th
centile was 1.58. In 614 (2%) cases the woman developed
pre-eclampsia and in this group there was an inverse
significant association between the gestational age at
delivery and prevalence of SGA (r = −0.99, P < 0.0001),
andbetween the gestational at delivery and mean uterine
artery PI (r = −0.51, P < 0.0001) and prevalence of
mean uterine artery PI above the 95th centile (r = −0.99,
P < 0.0001). The mean uterine artery PI was above the
95th centile in 77.2% of women who developed preeclampsia requiring delivery before 34 weeks, in 35.9%
of those delivering at 34–37 weeks and in 21.9% of those
delivering after37 weeks. The respective percentages were
82.3%, 46.9% and 28.8% for those with pre-eclampsia
and SGA, and 43.8%, 21.2% and 8.4% for those with
SGA but without pre-eclampsia.
Conclusions Pre-eclampsia requiring early delivery is
more likely to be associated with SGA than less severe
pre-eclampsia in women who deliver at term. Doppler
ultrasound assessment of the uterine arteries is more...