Prenatal screens can help sort out which women need to have more invasive tests to look for genetic conditions.
But invasive tests carry a small risk, so many people want to avoid them.
Still, current non-invasive screens are not perfect and may alarm couples needlessly or falsely reassure them.
In the quest to make these techniques better, looking at the tiny ear on a developing fetus could make a difference.
For the Jemsek family, life is dreamy.
They are enjoying time with their son Sawyer and are now preparing for the birth of another child. But this time around, there are a few more options to consider.
Meredith Jemsek is now 35, and that puts her at higher risk for delivering a baby with genetic abnormalities.
They wanted to know as soon as possible if the baby was OK, so at about 12 weeks, the Jemseks opted for the standard prenatal screens which include blood tests and ultrasounds to measure the back of the fetus' neck -- thickening in this area has a strong association with Down syndrome.
"It doesn't hurt me, doesn't hurt the baby and it's just to gather information and make informed decisions," said mother Meredith Jemske.
But the Jemsek screening actually involved more than what is usual -- something not normally measured was measured.
Dr. Norman Ginsberg with Reproductive Genetics Institute did a detailed exam of the angle of the fetus' ear.
"We know that Down syndrome children have low set ears and they're posteriorly rotated, which means they are turned back," Ginsberg said.
Doctors have known for years that the position and location of the ear is often abnormal in fetuses with Down syndrome and other chromosomal abnormalities.
But the ear was not always easy to see. Ginsberg says early research is showing advanced 3D technology now has the potential to make this ear screening more accurate.
"It's very exciting I think it's actually going to be the number one, most powerful marker compared to all the other things we look at," Ginsberg said.
In a pilot study online in the journal Prenatal Diagnosis, 348 pregnant women had a 3D-rendering of the fetal ear.
They also had more definitive chromosome tests. It was discovered 23 women had a fetus with a chromosomal abnormality through invasive testing and they were also flagged with the abnormal ear angle.
But it was not fool proof: of all those screened, there were 1 to 3 percent with an abnormal ear angle that had no chromosomal problems.
Rush University Medical Center obstetrician/gynecologist Jacques Abramowicz says even with 3D-imaging, getting a clear picture of the ear isn't always easy.
"At the moment, I cannot say it is the best and it will replace anything else it's probably an additional one and may help," Abramowicz said. "But at the moment, it is only in the research phase."
For the Jemseks, the ear screen offered an extra level of comfort early in the pregnancy but they still decided to go forward with more traditional definitive tests.
The Jemseks learned everything is fine.
Prenatal testing is not for everyone. Some couples choose not to have it.
Doctors can use other physical markers to help identify an increased risk of chromosome problems.
Dr. Ginsberg agrees more research is needed to confirm his findings.
Additionally, Ginsberg is also known in the United States as the "Father of Chorionic Villi Sampling" or CVS.
CVS is one of the well-established and definite invasive prenatal tests.
Reproductive Genetics Institute