PBS News Hour

AMNA NAWAZ: The Food and Drug Administration has approved a blood test that can identify pregnant women at severe risk for preeclampsia, a high blood pressure disorder that can develop during pregnancy.

As Stephanie Sy reports, the condition is a leading cause of maternal deaths worldwide.

STEPHANIE SY: Roughly one in 25 pregnancies in the U.S. is affected by preeclampsia, according to the Centers for Disease Control and Prevention.

If undetected and untreated, severe preeclampsia can cause maternal death.

In recent years, the condition accounted for about 6 percent of total maternal deaths in the U.S. Dr. Ravi Thadhani is executive vice president for health affairs at Emory University and co-author of a study that looked at this blood test.

Dr. Thadhani, thank you so much for joining the "NewsHour."

I understand there are already a variety of tests to check if a pregnant woman may have preeclampsia.

So what is different or better about this blood test?

DR. RAVI THADHANI, Executive Vice President For Health Affairs, Emory University: Stephanie, thank you for the question.

Preeclampsia is a hard condition to diagnose, but it's an even more difficult condition to predict.

This is the first test approved by the FDA to predict this terrible condition.

Importantly, it adds to a toolkit of other tests and measures that clinicians use.

We use blood pressure and a variety of blood tests.

But this particular test adds precision to the diagnosis and prediction of preeclampsia.

There are two important features of this test.

One is, it actually yields information before a woman actually gets sick.

So, as a prediction, it does really well.

And, secondly, it acts like a time clock, like a countdown, and tells you when she's going to get sick.

STEPHANIE SY: It is a terrible condition.

In fact, many of us will have heard of Tori Bowie, that track star who died just a month ago in childbirth.

She is believed to have had eclampsia at the time of her death, which really put a spotlight on this condition.

She was obviously very fit, as is former track star Allyson Felix, who also had preeclampsia during her pregnancy.

What does this tell us about who is at risk for this condition?

DR. RAVI THADHANI: Preeclampsia happens in about 5 to 7 percent of all women who get pregnant in the United States.

That's about 200,000 women.

Most preeclampsia happens at term, where it's mild.

It's really the preterm preeclampsia that we focus on, because, a woman, if she delivers preterm, the risks for the baby, of course, are incredibly high.

The only treatment we have for this condition is the delivery.

We know and understand some risk factors for this condition, Stephanie, high blood pressure, obesity, diabetes, in vitro fertilization, and so forth.

But we truly don't know the cause of this condition.

We have a better understanding of the biology as to who gets the condition.

The women that you mentioned, incredibly unfortunate.

We know that the condition affects Black woman at a rate of three to five times higher than women who are non-Black.

And while we don't understand why that's the case, we have a better understanding, like I said, of the disease overall.

And this test, of course, helps us with that.

STEPHANIE SY: Yes, I was going to ask who this test was for and whether you see this test as becoming something in routine pregnancy screening, and whether all women will have access to this blood test.

DR. RAVI THADHANI: So, what we did in this study, Stephanie, is, we studied women who came in to the hospital with high blood pressure.

So, clearly, they had some risk factor already.

And we used the test to predict -- or at least the test was able to predict who went on to get severe -- severe disease.

The risk factors, as I mentioned, high blood pressure, diabetes, in vitro fertilization, twin pregnancies, one can imagine the test first focused on those women with those risk factors.

But, unfortunately, there are women without any risk factors.

In fact, that represents the majority of women that get this condition.

And, again, we still don't understand why or when they get the condition.

As far as screening or routine use of this test, right now, it's only, I believe, going to be used in women at high risk for the condition.

STEPHANIE SY: And I understand that this test is already in use in Europe.

How widely might we see it be in use here in the U.S., where we have an extremely high maternal mortality rate, among the highest among developing nations?

DR. RAVI THADHANI: Yes, that's right.

Unfortunately, we have some of the highest maternal mortality rates.

I currently work in Georgia, and it ranks among the top states, but also in other parts of this country.

Really unfortunate.

The test is actually available in a few sites now.

And, certainly, as we roll into the summer and into the fall, the test will become much more widely available.

We have used this test in Europe, not by way of a full approval, but a conditional approval in Europe, and people use it and find it incredibly useful.

This, of course, represents the largest study that we have completed in the United States, demonstrating that the test has utility in the diversity of women that get pregnant and give birth here.

STEPHANIE SY: Well, it is certainly a toolkit that needs more tools to address maternal mortality.

Dr. Ravi Thadhani with Emory University, thanks so much for joining us with your expertise.

DR. RAVI THADHANI: Thank you, Stephanie.