New blood test predicts preeclampsia risk

A new blood test given in early pregnancy could prove a lifesaver, with research finding it may predict those at highest risk of developing preeclampsia.
 
Published in Nature Medicine, the Belgian study measured DNA methylation (cfDNAme) levels in the blood of almost 500 pregnant women at around 12 weeks gestation, correctly predicting the disorder in 57% of cases when also taking into account their medical history.
 
While this percentage falls short of other clinical tests, it does provide a simpler, earlier, and less intrusive option for patients, offering a new starting point for further research.
 
RACGP Expert Committee – Quality Care member Associate Professor Magdalena Simonis told newsGP the earlier preeclampsia is diagnosed and managed, the safer it is for mother and baby.
 
‘GPs play a key role here,’ she said.
 
‘Preeclampsia is a disease we have been trying to understand and prevent for decades, so if a simple blood test can detect an increased risk, this is a welcome advancement.
 
‘However, the gold standard remains to check the blood pressure at every visit and ask about rapid increase in swelling, headaches and reduction in fetal activity.’
 
According to the study, the placenta’s DNA floating outside of cells in the blood is altered in those who develop preterm preeclampsia.
 
Researchers were able to detect differences in cfDNAme in the control pregnancies when compared to those who developed preeclampsia.
 
Of those women, the test identified 38% of patients who went on to develop preeclampsia.
 
That number rose to 57% when testing was combined with risk factors such as having a family history of preeclampsia.
 
‘These preliminary results suggest that cell-free DNA methylation profiling is a promising tool for pre-symptomatic preeclampsia risk assessment and has the potential to improve treatment and follow-up in the obstetric clinic,’ the authors wrote.
 
Analysing maternal risk factors alone captured only one third of high-risk pregnancies.
 
While the exact cause of preeclampsia remains unknown, it is still a leading cause for peripartal morbidity worldwide, claiming 60,000 lives every year.
 
In Australia, around 5% of women are diagnosed with preeclampsia and one in 100 will experience severe complications.
 
It accounts for up to 10% of all preterm deliveries and leads to 20% of labour inductions and 15% of caesarean sections.
 
Associate Professor Simonis said taking a baseline blood pressure and measuring this at each visit is of most importance to GPs.
 
‘If a woman has a systolic blood pressure of 160 mmHg or greater on two consecutive occasions, although not diagnostic of preeclampsia this is significant and requires treatment and close monitoring,’ she said.
 
‘A diagnosis of preeclampsia is based upon the presence of hypertension and proteinuria. Preeclampsia is categorised as mild, moderate, and severe.’
 
University of Melbourne Translational Obstetrics Group Professor Tu’uhevaha Kaitu’u-Lino reviewed the Belgian research and told newsGP there is still a long way to go when it comes to understanding, predicting and treating preeclampsia.
 
‘The field desperately requires new and novel ways to identify who is at risk of developing preeclampsia, so that every woman receives the right care at the right time,’ she said.
 
‘I was excited to read about this research which offers a novel avenue for identifying those at risk early in their pregnancy.
 
‘It will be fascinating to see whether this new test has a part to play in future preeclampsia screening.’
 
In her News and Views article, Professor Kaitu’u-Lino referenced a test from the Fetal Medicine Foundation which detects 75% of preterm preeclampsia, and involves a blood test, ultrasound, a blood pressure reading and clinical history.
 
‘Although the cfDNAme test still falls short of the Fetal Medicine Foundation test in performance, the gap [57% versus 75% sensitivity] may be deemed worth it given that cfDNAme is simpler to apply,’ the review found.
 
The study’s authors concluded that while the findings are a step forward in preeclampsia risk prevention, further research is needed to validate the clinical use of their approach.
 
Professor Kaitu’u-Lino said what is really needed is a highly accurate test that can identify everyone at risk, and ideally a treatment which they could then be offered to halt disease progression. 
 
‘Both of these will go a long way in ensuring that every family gets to take a healthy baby home,’ she said.
 
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