Proposed clinical management of pregnancies after combined screening for pre-eclampsia at 30-34 weeks' gestation.
OBJECTIVE
To estimate the patient-specific risk of pre-eclampsia (PE) at 30-34 weeks' gestation by a combination of maternal characteristics and medical history with multiples of the median (MoM) values of mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum placental growth factor (PlGF) and serum soluble fms-like tyrosine kinase-1 (sFlt-1), and stratify women into high-, intermediate- and low-risk management groups.


METHODS
This was a prospective observational study in women attending a third-trimester ultrasound scan at 30-34 weeks as part of routine pregnancy care. Patient-specific risks of delivery with PE at < 4 weeks from assessment and at < 40 weeks' gestation were calculated using the competing-risks model to combine the prior risk from maternal characteristics and medical history with MoM values of MAP, UtA-PI, PlGF and sFlt-1. On the basis of these risks, the population was stratified into high-, intermediate- and low-risk groups. Different risk cut-offs were used to vary the proportion of the population stratified into each risk category and the performance of screening for delivery with PE at < 4 weeks from assessment and delivery with PE from 4 weeks after assessment and up to 40 weeks' gestation was estimated.


RESULTS
The study population of 8128 singleton pregnancies included 234 (2.9%) that subsequently developed PE. Using a risk cut-off of 1 in 50 for PE delivering at < 4 weeks and a risk cut-off of 1 in 150 for PE delivering at < 40 weeks' gestation, the proportion of the population stratified into high, intermediate and low risk was about 3%, 26% and 71%, respectively. The high-risk group contained 90% of pregnancies with PE at < 4 weeks and 40% of those with PE at 4 weeks from assessment to 40 weeks' gestation. The intermediate-risk group contained a further 49% of women with PE at 4 weeks from assessment to 40 gestational weeks. In the low-risk group, none of the women developed PE at < 4 weeks and only 0.3% developed PE at 4 weeks to 40 gestational weeks.


CONCLUSIONS
The study presents risk stratification of PE by the combined test at 30-34 weeks, aiming to identify a high-risk group in need of intensive monitoring from the time of the initial assessment and up to 40 weeks' gestation and an intermediate-risk group in need of monitoring from 4 weeks after the initial assessment and up to 40 weeks' gestation. All pregnancies would need to be reassessed at 40 weeks' gestation. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
Institute of Health Research, University of Exeter, Exeter, UK.
D
D
Wright
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
I
I
Dragan
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
A
A
Syngelaki
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.|Department of Fetal Medicine, Medway Maritime Hospital, Gillingham, UK.
R
R
Akolekar
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
K H
KH
Nicolaides
D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D000072483:Placenta Growth Factor / Q000097:blood*; D011225:Pre-Eclampsia / Q000175:diagnosis* / Q000378:metabolism; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000097:blood*; D011446:Prospective Studies; D012372:ROC Curve; D018608:Ultrasonography, Doppler / Q000379:methods; D016216:Ultrasonography, Prenatal / Q000379:methods; D055988:Uterine Artery / Q000000981:diagnostic imaging*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000097:blood*
C000608036:PGF protein, human; D000072483:Placenta Growth Factor; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1
mean arterial pressure; placental growth factor; pre-eclampsia; pyramid of antenatal care; soluble fms-like tyrosine kinase-1; uterine artery pulsatility index