Analysing blood from eight mothers who gave birth prematurely, the test was correct for six of them, misclassifying just one of the 26 full term deliveries.
Prof Basky Thilaganathan, a Royal College of Obstetricians and Gynaecologists spokesman, said: "Complications from premature birth are a leading cause of infant mortality and affect 7-8% of all births in the UK".
Dr. Stevenson is co-author of the researchers' published paper in Science, which is entitled "Noninvasive Blood Tests for Fetal Development Predict Gestational Age and Preterm Delivery". Estimates of menstrual periods can be imprecise.
While more research is needed before the test is ready for widespread use, experts say it has the potential to reduce fatalities and complications from the 15 million premature births per year worldwide. Provisional data for 2017 from the National Center for Health Statistics show that the preterm birth rate in the US has reached 9.93%, up from 9.86% in 2016, the third consecutive annual increase after steady declines over the previous seven years. "To date, no test on the market can reliably predict which pregnant moms will go on to preterm labor", comments Stacey D. Stewart, president of March of Dimes.
The free-floating genetic material has proven to be a powerful tool for detecting other problems, as well.
While we're still some way off a practical clinical test, early trials indicate this new method could one day replace the more expensive ultrasound as a method for gauging gestation, with the added bonus of providing warning signs of a premature birth. The estimates of gestational age given by the model were accurate about 45 percent of the time, which is comparable to 48 percent accuracy for first-trimester ultrasound estimates. Each blood sample was analyzed to identify expression levels of genes that were specific to the placenta and to the immune system, or were enriched in fetal liver.
"For the most part, we can't tell who is at risk for prematurity despite all the marvels of modern medicine", he wrote in an email. Further development and validation of an initial model resulted in the identification of a panel nine placenta-specific RNAs (CGA, CAPN6, CGB, ALPP, CSHL1, PLAC4, PSG7, PAPPA, and LGALS14) in maternal blood that could predict gestational age.
The team, at Stanford University, in the United States, say it is also as accurate as ultra-sound scans at predicting due dates.
To figure out how to predict preterm birth, the researchers used blood samples from 38 American women who were at risk for premature delivery because they had already had early contractions or had given birth to a preterm baby before. In validation tests in an independent cohort, they found that "the test accurately classified four of five preterm samples (80%) and misclassified three of 18 full-term samples (17%)".
The researchers report that their blood test demonstrated higher mean accuracy than methods based on mass spectroscopic measurements of the ratio of two proteins in blood [sex hormone binding globulin (SHBG) and insulin-like growth factor binding protein 4 (IBP4)], and also exhibited higher predictive value than ultrosonographic measurements of cervical length, or fetal fFN evaluation.
A newly developed blood test can predict the gestational age and preterm birth risks of expecting mothers.
"These cfRNA PCR-based tests have two advantages over alternatives: broader applicability and lower cost", they conclude. These tests hold promise for prenatal care in both the developed and developing worlds....