New Blood Test Could Predict Exact Due Date for Pregnant Women

Stanford University scientists can now determine whether a mother will have a premature birth with up to 80 percent accuracy.
Shelby Rogers

A new blood test is taking more guesswork out of pregnancy. Stanford University scientists created a blood test that can predict a woman's due date (or her gestational age) just as reliably and less expensively than any ultrasound. 

The technique could also play an important role in determining whether the pregnancy will lead to a premature birth. The blood tests have done so with 75-80 percent accuracy, according to the Stanford University team. 

Over 15 million infants worldwide are born prematurely. Doctors have never had reliable resources to determine whether a baby will be born prematurely, especially in areas lacking the funding or technology to help doctors care for mothers in those situations. 

The tests measure genetic activity in the maternal, placental, and fetal genes. It takes a look at the mother's blood levels of cell-free RNA. RNA is the body's messenger to "protein-making factories." The blood samples collected during a pregnancy can determine which genes gave accurate readings of gestational age and risk of premature births.

"We found that a handful of genes are very highly predictive of which women are at risk for preterm delivery," said professor Mads Melbye, who is also president and CEO of the Statens Serum Institute in Copenhagen. "I've spent a lot of time over the years working to understand preterm delivery. This is the first real, significant scientific progress on this problem in a long time."

The team behind the new blood test includes professor of bioengineering and applied physics Stephen Quake. Quake authored the paper published online in Science with visiting professor of medicine Melbye. The lead authors are former postdoc Thuy Ngo and grad student Mira Moufarrej. Together, Quake said the team represented the best of medical collaboration. 


"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."

Premature birth qualifies as a baby's arrival three weeks early. In the United States alone, premature births account for 9 percent of all births each year. It's also the largest cause of infant mortality and the biggest cause of death of children under 5 in the world. But for Quake, the project hits particularly close to home. 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. 

The gestational age testing could give scientists more than an accurate read on a woman's due date. It could open up a better understanding of how babies develop and how a mother's body responds to that growth.