Proposed clinical management of pregnancies after combined screening for pre-eclampsia at 35-37 weeks' gestation

Ultrasound Obstet Gynecol. 2017 Sep;50(3):383-387. doi: 10.1002/uog.17419. Epub 2017 Jul 26.

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.

Conclusion: 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.

Keywords: mean arterial pressure; placental growth factor; pre-eclampsia; pyramid of antenatal care; soluble fms-like tyrosine kinase-1; uterine artery pulsatility index.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Arterial Pressure
  • Biomarkers / blood
  • Female
  • Humans
  • London
  • Placenta Growth Factor / blood
  • Pre-Eclampsia / blood
  • Pre-Eclampsia / diagnosis*
  • Pre-Eclampsia / diagnostic imaging
  • Pre-Eclampsia / prevention & control
  • Pregnancy
  • Pregnancy Outcome
  • Pregnancy Trimester, Third
  • Prenatal Diagnosis*
  • Prospective Studies
  • Pulsatile Flow
  • Risk Factors
  • Umbilical Arteries / physiopathology
  • Vascular Endothelial Growth Factor Receptor-1 / blood

Substances

  • Biomarkers
  • PGF protein, human
  • Placenta Growth Factor
  • FLT1 protein, human
  • Vascular Endothelial Growth Factor Receptor-1