One condition you’ll be actively monitored for during pregnancy is preeclampsia. It can cause serious complications for mom and baby, and early detection is key for treatment. Yet doctors often can’t diagnose preeclampsia until symptoms or signs, including high blood pressure, appear. Now, a blood test could give patients an earlier way to know if they’re at high risk for the condition.

While doctors say more tools to help combat preeclampsia are always welcome, there are a few things they want expectant moms to keep in mind before buying in (spoiler alert: this test is expensive!). Here’s what you should know. 

What Is Preeclampsia? 

Preeclampsia is a sudden onset of high blood pressure that impacts more than 3% of American women during pregnancy.[1] Preeclampsia and eclampsia (the severe form of preeclampsia involving maternal seizures) cause 14% of maternal deaths around the world each year, according to the World Health Organization (WHO).[2]

If left untreated, preeclampsia can prevent your baby from getting enough oxygen, damage your kidneys and liver, and rarely lead to seizures and stroke. Having preeclampsia may also mean that you need to deliver early, raising the risk of complications for your baby.[3] The condition usually develops after 20 weeks of pregnancy, and typically in the third trimester. A significant number of women can also develop postpartum preeclampsia after they give birth. 

How do doctors currently assess your risk for preeclampsia? 

During prenatal appointments, your doctors consider your family history, current pregnancy health and past health conditions to determine your risk of developing preeclampsia, says Michael Carson, M.D., founder of Carson Internal Medicine and a professor of medicine and OB/GYN at the Hackensack Meridian School of Medicine. 

Women who fall into the “high risk” category include those with conditions such as chronic high blood pressure, kidney disease, diabetes or autoimmune conditions like lupus. Having had preeclampsia in a previous pregnancy or carrying multiples can also deem you as high risk. 

Other moderate risk factors include being pregnant for the first time, having used IVF, or being pregnant more than 10 years after your last pregnancy. There are also some demographic factors that lead doctors to monitor you more closely, such as being 35 or older, being Black, or meeting criteria for lower socioeconomic status.

While those factors determine your risk level, the condition isn’t actually diagnosed until a patient develops high blood pressure and protein in the urine, explains Christine Greves, M.D., an OB/GYN at the Winnie Palmer Hospital for Women and Babies in Orlando, Florida.

Could a blood test better determine your risk factor? 

The new blood test called Encompass was developed by biotech company Mirvie to look at RNA (a molecule that carries instructions from DNA to create certain proteins) to assess the health of your placenta and how your pregnancy is progressing. The test is performed between weeks 18 and 22 of pregnancy and is very convenient: A mobile phlebotomist comes to your home to draw your blood. You get results within two weeks. 

So far it has a pretty good track record for early risk detection. The test maker claims a 90%-plus rate of accurately predicting whether you’ll go on to develop preeclampsia. The test predicted nine of 10 pregnancies that later developed preeclampsia, according to a study conducted by the company of nearly 11,000 pregnancies. It also found that women who were classified as “low risk” had a 99.7% chance of not developing preeclampsia before their baby was born.[4] 

“Any blood test that would help us to be able to risk-stratify patients is important for prevention,” says Taraneh Shirazian, M.D., an OB/GYN with NYU Langone Health.

But doctors don’t all agree that Encompass is a better metric for determining preeclampsia risk compared to typical monitoring.

What to consider before taking the Encompass test  

Women are already regularly assessed for preeclampsia throughout their pregnancies via monitoring blood pressure and urine, whether they're high risk or low, says Eran Bornstein, M.D., director of the Center for Maternal-Fetal Medicine at Northwell Lenox Hill Hospital in New York City and president of Fetal Medicine Foundation. 

Your doctor may direct you to a free screening tool that lets you plug in personal elements like blood pressure, certain blood biomarkers and other risk factors.

Testing positive on the Encompass test may help patients not otherwise at a known risk be identified as benefiting from a baby aspirin regimen. But doctors will continue to monitor your blood pressure and test your urine regardless of what your risk is, points out Dr. Carson. 

“A negative test means that her risk is lower, but not zero,” he says. “Because preeclampsia is a serious disease that should be detected early, her physicians will continue the routine monitoring. The test is not a ‘go’ or ‘no-go’ signal. It can risk-stratify, but preeclampsia can occur any time and postpartum as well.”

As a laboratory-developed test, Encompass is not subject to regulation by the Food and Drug Administration (FDA). The test is, however, certified by the Centers for Medicare and Medicaid Services (CMS) under the Clinical  Laboratory Improvement Amendments (CLIA) to perform high-complexity clinical testing, explains Carrie Haverty, a genetic counselor and vice president of product at Mirvie. 

Encompass can be expensive — $1,850 out of pocket. You can check with your insurance provider to see if it is covered under your policy. Discounts may be offered through Mirvie or third parties that use Encompass in their healthcare programs. You also can use your Flexible Spending Account (FSA) and/or Health Savings Account (HSA) for this, according to Haverty. 

The test is currently limited to pregnant women who will be 35 or older when they give birth — a risk factor for preeclampsia — and who don’t have a history of high-risk factors like having had preeclampsia in the past or chronic high blood pressure. “Our goal is to make it available to more people in the future,” Haverty says.

That cost is a big issue for healthcare providers. “The majority of women in the U.S. cannot afford a $1,850 test,” Dr. Shirazian says.

You’re flagged as high risk for preeclampsia — now what?  

Testing and monitoring for preeclampsia is crucial because it allows doctors to intervene quickly, says Dr. Greves. If you’re at high risk for developing preeclampsia, your healthcare provider will likely recommend that you take low-dose aspirin between 12 weeks and 28 weeks of your pregnancy.[9]

From there, you’ll likely be referred to a high-risk obstetrician or maternal-fetal medicine specialist and undergo extra monitoring, including possibly doing daily blood pressure readings at home, Dr. Greves says. If your blood pressure stays high, your healthcare team may suggest inducing you early.

If you’re interested in taking the Encompass test and you can afford it, doctors do say you can go for it. “Having more tools for preeclampsia is helpful, and it’s very important to come up with new technology that will help the masses,” Dr. Shirazian says. “But it needs to be cost-effective to be equitable.”