The effect of gestational age and placental location on the prediction of pre-eclampsia by uterine artery Doppler velocimetry in low-risk nulliparouswomen
A. Antsaklis et al., The effect of gestational age and placental location on the prediction of pre-eclampsia by uterine artery Doppler velocimetry in low-risk nulliparouswomen, ULTRASOUN O, 16(7), 2000, pp. 635-639
Objective To assess how placental position and gestational age ran influenc
e the value of a diastolic notch of the uterine arteries as a screening tes
t for pre-eclampsia. In a low-risk population of healthy nulliparous women.
Methods Color Doppler ultrasound was used to examine both uterine arteries
in 654 healthy nulliparas at 4-week intervals between 20 and 32 weeks. The
only criterion for an abnormal result was the presence of an early diastoli
c notch. In each subject the placental position was also recorded. The majo
r end points were pre-eclampsia and pre-eclampsia requiring delivery before
the 34th week.
Results Ninety-eight women (15%) had abnormal flow velocity waveforms at th
eir first visit. Twenty-one out of 654 women developed ere-eclampsia (3.2%)
. The sensitivity of the test became lower as gestational age advanced and
ranged from 81% at 20 weeks, to 71.4% at 32 weeks. In contrast, the specifi
city and positive predictive value increased significantly. Eleven out of 1
2 women who delivered before 34 weeks had abnormal waveforms at the 24th we
ek. In women with a full lateral placenta, the predictive value of the test
was extremely low, especially in cases with unilateral notches.
Conclusion Pre-eclampsia can be more accurately predicted if, along with th
e presence of a notch, both gestational age and placental position ale take
n into account. At week 24 the test maintains a high sensitivity (76.1%), b
ut also has an improved specificity (95.1%) and positive predictive value (
34%), which allow the clinician to intervene with a potential preventive tr
eatment.