Uterine artery Doppler, birth weight and timing of onset of pre-eclampsia: providing insights into the dual etiology of late-onset pre-eclampsia.
OBJECTIVE
To investigate the relationship between uterine artery Doppler ultrasound indices and birth weight in women with early-, intermediate- and late-onset pre-eclampsia as compared with women with uneventful pregnancy outcome.


METHODS
In a retrospective, observational cohort study, uterine artery Doppler assessment was carried out at 18+0 to 23+6 weeks' gestation in 26,893 women attending for routine antenatal care in a tertiary care center. The mean resistance index (RI) and its relationship to the outcome of pregnancy and birth-weight centiles were evaluated.


RESULTS
Uterine artery RI showed a significant, negative correlation with birth weight (r= -0.20, P<0.0001). Patients with early-onset pre-eclampsia had an increased prevalence of high uterine artery mean RI, above the 90(th) centile, corresponding to an increased proportion of small-for-gestational age (SGA) neonates with a birth weight below the 10(th) centile. In late-onset pre-eclampsia, however, there was an unexpectedly higher proportion of large-for-gestational-age (LGA) neonates with a birth weight above the 90(th) centile without a concurrent increase in the prevalence of low uterine artery mean RI below the 10(th) centile.


CONCLUSIONS
The finding of a bimodal skewed distribution of birth weight, with neonates exhibiting a higher prevalence of both LGA and SGA with late-onset pre-eclampsia, indicates that there are two types of late-onset pre-eclampsia. These findings explain the poor performance of mid-trimester uterine artery Doppler in predicting pre-eclampsia at term and provide insights into the placental origins of the early and late forms of pre-eclampsia.
Department of Obstetrics, Charité University Medicine Berlin, Berlin, Germany; Fetal Medicine Unit, St George's Hospital NHS Healthcare Trust, London, UK.
S
S
Verlohren
K
K
Melchiorre
A
A
Khalil
B
B
Thilaganathan
D000328:Adult; D001724:Birth Weight; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D021041:Placental Circulation; D010927:Placental Insufficiency / Q000000981:diagnostic imaging*; D011225:Pre-Eclampsia / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000517:prevention & control; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011673:Pulsatile Flow; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal; D006113:United Kingdom / Q000453:epidemiology; D055988:Uterine Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology
large-for-gestational-age; pre-eclampsia; resistance index; small-for-gestational age; uterine artery Doppler