Stratification of pregnancy care based on risk of pre‐eclampsia derived from biophysical and biochemical markers at 19–24 weeks' gestation

Abstract

The performance of screening at 19-24 weeks' gestation for pre-eclampsia (PE) with delivery at < 28, < 32 and < 36 weeks' gestation achieved by a combination of maternal demographic characteristics and medical history, uterine artery pulsatility index (UtA-PI) and mean arterial pressure (MAP) is improved by the addition of serum placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1). The performance of screening for PE at ≥ 36 weeks' gestation is poor irrespective of the method of screening at 19-24 weeks. What are the clinical implications of this work?It is proposed that all pregnant women should have assessment of risk for PE at 20 and 36 weeks' gestation, and the 20-week visit can be used to define subgroups requiring additional monitoring and reassessment at 28 and 32 weeks. If the 20-week visit includes measurement of serum PlGF and sFlt-1, in addition to UtA-PI and MAP, the proportion of the population requiring additional monitoring and reassessment at 28 and 32 weeks is substantially reduced.

Development and validation of model for prediction of placental dysfunction‐related stillbirth from maternal factors, fetal weight and uterine artery Doppler at mid‐gestation

“…The first stage involves screening for pre-eclampsia at 11-13 weeks' gestation, by a combination of maternal risk factors, mean arterial pressure, uterine artery pulsatility index (UtA-PI) and serum placental growth factor or pregnancy-associated plasma protein-A, and treatment of the high-risk group with aspirin [4][5][6][7][8][9][10] . The second stage, at 19-24 weeks, aims to identify a high-risk group that would benefit from close monitoring for early diagnosis of pre-eclampsia and a SGA fetus and prevention of stillbirth by defining the best approach to monitoring and timing of delivery [11][12][13][14][15][16][17][18] .…”

Contingent screening in stratification of pregnancy care based on risk of pre‐eclampsia at 19–24 weeks' gestation

“…Patient-specific risks of delivery with PE at < 28, < 32 and < 36 weeks' gestation were calculated using the competing-risks model to combine the prior distribution of gestational age at delivery with PE, obtained from maternal demographic characteristics and medical history 23 , with multiples of the median (MoM) values of UtA-PI, MAP, PlGF and sFlt-1 15,16,[24][25][26][27] . The performance of screening was assessed by plotting the detection rate against the screen-positive rate at fixed risk cut-offs.…”

“…In previous studies, we proposed the concept of stratification of the population into management groups based on the estimated risk for PE by combinations of maternal factors, UtA-PI, MAP, PlGF and sFlt-1 at 19-24 weeks' gestation [13][14][15][16] . In this study, we compared the detection rate and screen-positive rate, at fixed risk cut-offs, of delivery with PE at < 28, < 32 and < 36 weeks' gestation in screening by different combinations of biomarkers.…”

“…we proposed that the population can be stratified into very high‐risk, high‐risk, intermediate‐risk and low‐risk groups (Figure 1) 16 . The very high‐risk group would require close monitoring for high blood pressure starting from 24 weeks, the high‐risk group together with the undelivered pregnancies from the very high‐risk group would require close monitoring for high blood pressure starting from 28 weeks, and the intermediate‐risk group together with the undelivered pregnancies from the very high‐ and high‐risk groups would have reassessment of risk for PE at 32 weeks to identify those that would require close monitoring at 32–35 weeks.…”

“…All pregnancies, including the low‐risk group, would have reassessment of risk for PE at 36 weeks to define the plan for further monitoring and delivery. We found that assessment of risk of delivering with PE before 36 weeks' gestation by a combination of maternal demographic characteristics and medical history with uterine artery pulsatility index (UtA‐PI), mean arterial pressure (MAP) and serum placental growth factor (PlGF) and soluble fms‐like tyrosine kinase‐1 (sFlt‐1) was superior to screening by maternal factors, UtA‐PI and MAP alone 16 .…”