A new study has discovered an alternative way to screen for pre-eclampsia in pregnant women. The new screening method may be even more accurate than current methods.
The Screening ProgRamme for prE-Eclampsia (SPREE) challenges the current guidelines in the UK on how hypertensive disorders should be managed during pregnancy.
“Preeclampsia is a presence of high blood pressure in a woman that has a normal blood pressure after 20 weeks of gestation with presence of protein in urine,” says Medplux. Preeclampsia affects about 2%-3% of pregnancies.
Recent evidence suggests that giving low-dose aspirin to women who are at high risk of preeclampsia can reduce the prevalence of the most severe form of the disorder by 60%. However, treatment must be started before 16 weeks’ gestation for it to be effective. Early screening is crucial, and the National Institute for Health and Care Excellence (NICE) uses a checklist of characteristics as well as medical history to determine a patient’s risk level.
Under the NICE guidelines, women are to be considered at risk for preeclampsia if they have one “major” factor from the list, which includes: chronic kidney disease, hypertensive disease in a previous pregnancy, autoimmune disease, chronic hypertension and diabetes mellitus.
Women are also considered at risk if they have two of the moderate factors, which includes: a gap of 10 years in between pregnancies, first pregnancy at aged 40 or older, a body mass index (BMI) over 35 and a family history of preeclampsia.
Liona Poon, MD and co-senior author, says the trouble with the NICE method is that it treats each risk factor as a separate screening test.
“At a false-positive rate of 10 percent, the NICE method achieves a detection rate of 42 percent for preterm preeclampsia,” she says.
The new study compares the performance of first-trimester screening with an alternative approach to the current NICE approach.
The study was conducted at seven English NHS (National Health Service) maternity hospitals between April and December 2016.
Preeclampsia (PE) occurring at any point during pregnancy, known as all-PE, was found in 2.8% of the pregnancies involved in the study. Preterm-PE was found in 0.8% of pregnancies. Detection rates for the NICE approach for all-PE and preterm PE were 30.4% and 40.8% respectively. Detection rates for the first-trimester combined test for all-PE and preterm PE were 42.5% and 82.4% respectively.
The study’s findings indicate that the new method, a simple algorithm based on maternal characteristics and measurable markers, can correctly identify about 80% of women who would develop preterm-PE and benefit from taking aspirin as a preventative measure.
“The SPREE study has provided definitive proof to support risk-based screening for preterm-PE using various biomarkers,” says Poon. “It is now time to revise the professional guidelines and to move away from using a checklist-based method for screening.”
The screening is based on the Bayes’ theorem method, which combines maternal risk factors with certain biomarkers.
The combined test is available as both an app and a risk calculator at the Fetal Medicine Foundation website.