Published: Sun, June 10, 2018
Medical | By

Blood test could predict pregnancy due date, potential for preterm birth

Blood test could predict pregnancy due date, potential for preterm birth

It works as reliably as ultrasound, the current standard, and is better suited to low-resource settings, making it potentially useful for boosting global maternal health, the researchers said. "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". Provisional data for 2017 from the National Center for Health Statistics show that the preterm birth rate in the USA has reached 9.93%, up from 9.86% in 2016, the third consecutive annual increase after steady declines over the previous seven years.

The same approach can also be used during the first trimester to estimate the due date with about 45 percent accuracy - a rate similar to ultrasound, a more expensive and invasive test. In general, there is a difficulty in predicting precisely the date of all births.

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". A blood test to detect Down syndrome that was developed by Quake's team in 2008 is now used in more than 3 million pregnant women per year, he noted. The latest research evaluated whether the same method could be developed into blood tests for estimating both gestational age and the risk of preterm birth.

The test detected the variations in RNA in a pregnant woman's blood and estimated due dates within two weeks in almost half the cases. "We had this idea that we could make a molecular clock to see how these things change over time and it should allow you to measure gestational age and see where things are in pregnancy".

The research team conducted a pilot study on 31 healthy pregnant women, using 21 of them to create a statistical model based on nine transcripts of RNA from the mother's immune system, the infant's liver, and the placenta.

To figure out how to predict pre-term birth, the researchers used blood samples from 38 women who were at risk for premature delivery. "Our results are thus generally comparable to ultrasound measurements, can be performed throughout pregnancy, and do not require a priori physiological knowledge such as the woman's last menstrual period", the team states. From seven cfRNA biomarkers, six out of eight preterm cases were correctly identified.

They acknowledge that their studies will need verifiying in much larger, ethnically diverse cohorts, including women who aren't already known to be at risk of preterm birth.

"It's mostly maternal genes", Moufarrej said, noting that the genes that predict prematurity are different than those that give information about gestational age.

It has been found that certain genes give "signals" from which the risk of premature birth can be calculated even two months earlier than expected. The women gave blood samples during the second or third trimester of their pregnancy, and of them, 15 ended up having preterm deliveries.

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