Blood Test In Pregnant Women Identifies Those At Risk of Preterm Delivery

New blood test predicts with 75-80 percent accuracy, whether a woman’s pregnancy will end in preterm delivery. The test has been developed by a joint team of scientists from across the world, led by scientists at Stanford University. It is hoped the test will help reduce problems associated with preterm births which impact nearly 15 million babies globally each year. The details of the blood tests are elaborated in a paper that will appear online in the journal Science. Senior authors of the study are Stephen Quake, PhD, professor of bioengineering and of applied physics at Stanford, and Mads Melbye, MD, visiting professor of medicine. The lead authors include former Stanford postdoctoral scholar Thuy Ngo, PhD, and Stanford graduate student Mira Moufarrej.

"This work is the result of a fantastic collaboration between researchers around the world," said Quake, who is also the Lee Otterson Professor in the School of Engineering. "We have worked closely with the team at the Stanford March of Dimes Prematurity Research Center, and the research involved collaborations with scientists in Denmark, Pennsylvania and Alabama. It's really team science at its finest."

Accurate and Inexpensive Tests To Predict Preterm Labor and Estimate FetalGestational Age – Need of the Hour

• Currently doctors lack reliable tests or methods to accurately predict women at risk for preterm labor and the problem continues to be a major cause of infant mortality worldwide. In two-thirds of cases, women spontaneously go into preterm labor and the doctors are unable to find the reason.
  
  Previously available tests were only employed in high-risk women, such as those who had already had a history of preterm labor, and accuracy rate was just 20 percent.

Quake first developed a personal interest in this problem when he became a parent: his daughter was born nearly a month premature. "She's now a very healthy and active 16-year-old, but it certainly stuck in my mind that this is an important problem to work on," Quake said.

• Additionally, the team feel that better and cheaper tests are required to correctly estimate fetal gestational age. Currently ultrasound scan in the first trimester is performed to estimate the woman’s expected due date but the accuracy decreases with gestational age and therefore scans are not reliable in women who have not received early antenatal care. Also ultrasound scanning requires costly equipment and trained personnel which may not be readily available in low resource settings.

The study team hope that their blood test would be inexpensive and simple to use in low resource settings as well.

Details of Study – Predicting Preterm Labor And Estimating Fetal Age

Estimating Gestational Age of Fetus (baby in the womb)

• The test to estimate gestational age was developed by studying a cohort of 31 Danish women who gave their blood every week throughout their pregnancies. All the women had full-term pregnancies.
• First, the team used blood samples from 21 of these women to develop a statistical model, which identified nine cell-free RNAs formed by the placenta that could predict gestational age, and validated the model using blood samples from the remaining 10 women.
• The accuracy of the estimating fetal gestational age was 45 percent, which is comparable to 48 percent accuracy for first-trimester ultrasound estimations.

Measuring cell-free RNA in mothers' blood also could provide a whole lot of information about fetal development and growth, Ngo said. "This gives a super-high resolution view of pregnancy and human development that no one's ever seen before," she said. "It tells us a lot about human development in normal pregnancy."

Predicting Preterm Birth

• To predict risk of preterm birth, the scientists used blood samples from 38 American women who were at risk for premature delivery because they had a previous history of preterm delivery or had suffered from premature contractions already
• Each of these women gave one blood sample either during the second or third trimester of their pregnancies.
• Of this group, 13 women delivered preterm, and the remaining 25 delivered at term.
• The scientists demonstrated that levels of cell-free RNA from seven maternal and placental genes could correctly predict those pregnancies that would end early

"It's mostly maternal genes," Moufarrej said, noting that the genes that predict prematurity are different than those that give information about gestational age. "We think it's mom sending a signal that she's ready to pull the ripcord."

Future Plans

• The team plan to validate these new blood tests in larger numbers of pregnant women before they can be made available for routine clinical use
• They plan to further elucidate the roles of genes associated with preterm labor and gain deeper insight into the reasons for the event
• The scientists also plan to identify drug targets that could prevent or delay preterm births

References:

1. Blood Test Provides More Accurate Prenatal Testing For Down Syndrome - (https://www.npr.org/sections/health-shots/2014/02/26/282095202/blood-test-provides-more-accurate-prenatal-testing-for-down-syndrome)
2. Risk of Preterm Birth Reliably Predicted by New Test - (https://www.ucsf.edu/news/2018/05/410456/risk-preterm-birth-reliably-predicted-new-test)

Advertisement

Source-Medindia