A simple pregnancy blood test could help warn of preterm babies

A new blood test could flag pregnant women at risk of giving birth prematurely, giving healthcare providers a vital insight into potential risks to both parent and child. The new test relies on identifying chemicals in the mother's bloodstream that affect the gene activity within the child.

The scientists' theory was that so-called cell-free ribonucleic acid, or cfRNA, could act as a benchmark for fetus development. RNA acts as a messenger, transferring instructions from DNA to control how proteins synthesize in cells. During pregnancy, cfRNA in the mother affects – and reflects – how far through development the fetus is.

"By measuring cell-free RNA in the circulation of the mother, we can observe changing patterns of gene activity that happen normally during pregnancy, and identify disruptions in the patterns that may signal to doctors that unhealthy circumstances like preterm labor and birth are likely to occur," Dr. David K. Stevenson, M.D., principal investigator of the March of Dimes Prematurity Research Center at Stanford University, said of the findings.

The team looked at two separate groups of women, all of whom were deemed to be at an elevated risk of preterm delivery. Researchers then identified set of cfRNA transcripts that could be used to classify women that would deliver up to two months ahead of labor. From seven cfRNA biomarkers, six out of eight preterm cases were correctly identified.

At the same time, another part of the study looked at a separate group of pregnant women. They had blood samples taken on a weekly basis until they gave birth – on time – from which the research team was able to identify nine cfRNA biomarkers that related to gestational age. While it's not exact, with accuracy at 45-percent, it's still close to the current benchmark method of ultrasound, which is 48-percent accurate.

Although slightly less accurate, the blood test could be cheaper than ultrasound methods, March of Dimes points out. For premature birth, meanwhile, there's no current test to predict if that's likely to take place. That's despite it affecting around 15m babies worldwide each year.

The hope is that not only will this new test give healthcare providers earlier warnings that a preterm birth is possible, it might also shape new ways to avoid the situation altogether. "With further study," Dr. Stevenson suggests, "we might be able to identify specific genes and gene pathways that could reveal some of the underlying causes of preterm birth, and suggest potential targets for interventions to prevent it."

Next up will be larger-scale, blinded clinical trials, March of Dimes says, to validate the results.

IMAGE California DFG