title: Proposed clinical management of pregnancies after combined screening for pre-eclampsia at 35-37 weeks' gestation.
abstract: OBJECTIVE
  To estimate the patient-specific risk of pre-eclampsia (PE) at 35-37 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 35-37 weeks as part of routine pregnancy care. Patient-specific risks of delivery with PE at < 4 weeks from assessment and PE at < 42 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 < 40 and ≥ 40 weeks' gestation was estimated.
  
  
  RESULTS
  The study population of 3703 singleton pregnancies included 38 (1.0%) with PE < 40 weeks' gestation and 22 (0.6%) with PE ≥ 40 weeks. Using a risk cut-off of 1 in 50 for PE delivering at < 4 weeks after assessment to define the high-risk group and a risk cut-off of < 1 in 100 for PE delivering at < 42 weeks' gestation to define the low-risk group, the proportion of the population stratified into high, intermediate and low risk was 12.7%, 28.8% and 58.5%, respectively. The high-risk group contained 92% of pregnancies with PE at < 40 weeks' gestation and 73% of those with PE at ≥ 40 weeks. The intermediate-risk group contained a further 27% of women with PE at ≥ 40 weeks. In the low-risk group, none of the women developed PE at < 40 or ≥ 40 weeks' gestation.
  
  
  CONCLUSIONS
  The study presents risk stratification of PE by the combined test at 35-37 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, an intermediate-risk group in need of reassessment at 40 weeks' gestation and a low-risk group that can be reassured that they are unlikely to develop PE. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Panaitescu
authors.affiliation: Institute of Health Research, University of Exeter, Exeter, UK.
authors.forename: D
authors.initials: D
authors.lastname: Wright
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Militello
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.|Department of Fetal Medicine, Medway Maritime Hospital, Gillingham, UK.
authors.forename: R
authors.initials: R
authors.lastname: Akolekar
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000328:Adult; D062186:Arterial Pressure; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008131:London; D000072483:Placenta Growth Factor / Q000097:blood; D011225:Pre-Eclampsia / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000517:prevention & control; D011247:Pregnancy; D011256:Pregnancy Outcome; D011263:Pregnancy Trimester, Third; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D011673:Pulsatile Flow; D012307:Risk Factors; D014469:Umbilical Arteries / Q000503:physiopathology; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000097:blood
chemical_list: D015415:Biomarkers; C000608036:PGF protein, human; D000072483:Placenta Growth Factor; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1
keywords: mean arterial pressure; placental growth factor; pre-eclampsia; pyramid of antenatal care; soluble fms-like tyrosine kinase-1; uterine artery pulsatility index