Contingent screening for preterm pre-eclampsia

Area of Science:

• Maternal-Fetal Medicine
• Obstetric Ultrasound
• Biomarker Research

Background:

• Preterm pre-eclampsia (PE) poses significant risks to maternal and fetal health.
• Current screening involves a combination of maternal factors, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), and serum placental growth factor (PlGF).
• Optimizing screening protocols to improve efficiency and accessibility is crucial.

Purpose of the Study:

• To evaluate a two-stage screening strategy for preterm PE.
• To assess the feasibility of routine screening using maternal factors and MAP, reserving advanced markers (UtA-PI, PlGF) for high-risk subgroups.
• To determine the detection rates (DR) and false-positive rates (FPR) of this stratified approach.

Main Methods:

• Prospective screening data from women at 11-13 and 19-24 weeks' gestation.
• Bayes' theorem applied to derive a-priori risk from maternal factors and MAP.
• Second-stage screening using UtA-PI and PlGF for intermediate-risk groups to calculate posterior risk.

Main Results:

• At 11-13 weeks, a two-stage approach achieved a 74% DR for preterm PE at a 10% FPR, using UtA-PI/PlGF in only 50% of the population.
• Reducing second-stage screening to 30% of the population resulted in a minimal DR decrease to 71%.
• At 19-24 weeks, a similar DR (84%) was achieved with UtA-PI/PlGF in 70% of cases; reducing this to 40% lowered DR to 81%.

Conclusions:

• A two-stage screening protocol for preterm PE is effective in both early and mid-pregnancy.
• This strategy allows for widespread initial screening using maternal factors and MAP, followed by targeted use of UtA-PI and PlGF.
• This optimized approach can maintain high detection rates while potentially reducing the need for universal advanced marker testing.