New screening method may better predict preeclampsia early in first pregnancy

A more personalized screening approach for a potentially life-threatening pregnancy complication related to blood pressure could better predict the condition during the first trimester, when it may still be preventable, new research suggests.

The study, published Monday in the American Heart Association journal Hypertension, showed a screening algorithm that combines maternal history, ultrasound data and several tests for blood markers could more effectively predict who will develop preeclampsia during their first pregnancy than current risk factor guidelines.

"Preeclampsia is one of the most severe illnesses of pregnancy and may lead to preterm birth and/or maternal death," senior study author Dr. Emmanuel Bujold said in a news release. He is a professor in the department of obstetrics and gynecology at the Université Laval in Québec City, Canada.

"The good news is that we now have a more precise screening approach using existing tests that can predict preeclampsia early in pregnancy," he said. "The next step is to make this screening available to all pregnant women so that more women could receive a diagnosis early in pregnancy" and begin preventive treatment.

Preeclampsia – a dangerous form of high blood pressure that affects 1 in 25 pregnancies in the U.S. – is a leading cause of maternal death worldwide. It is diagnosed when blood pressure reaches or passes 140/90 mmHg, is more common in first pregnancies and begins developing during the first 12 weeks. Symptoms often do not appear before week 20. They may include headaches, vision changes and swelling of the mother's hands, feet, face or eyes or a change in the baby's well-being.

Recent research has linked preeclampsia to an increased risk of developing cardiovascular complications later in life.

Current guidelines from the American College of Obstetricians and Gynecologists encourage pregnant women to take aspirin if they have a major risk factor, such as chronic high blood pressure, Type 2 diabetes, chronic kidney disease, lupus or had preeclampsia during a prior pregnancy. Aspirin is also recommended for pregnant women with two moderate risk factors, such as being a Black woman, having a family history of preeclampsia, having a first pregnancy, obesity or an in vitro fertilization pregnancy.

Prior studies by the Fetal Medicine Foundation have shown that a combination of maternal health history and ultrasound and blood biomarker tests during the first trimester can predict preeclampsia that develops before the 37th week of gestation.

In the new study, researchers used the FMF screening model specifically in women who were pregnant for the first time. They wanted to see if they could better predict preterm preeclampsia before the 37th week and early-onset preeclampsia before the 34th in 7,325 women across five health centers in Canada.

The women, who were an average 29 years old and mostly white, were between 11 and 14 weeks pregnant when the study began. Preterm preeclampsia developed in 65 women and early-onset preeclampsia occurred in 22.

The new screening model predicted preterm preeclampsia in 63% of cases and early-onset preeclampsia in 77%, with a false positive rate of 16%. The algorithm outperformed ACOG criteria, which would have detected 62% of preterm preeclampsia cases and 59% of early-onset cases, with a false positive rate of 34%.

Once preeclampsia develops, the only way to resolve it is by delivering the baby. But the condition can be prevented. In a prior meta-analysis, the researchers found taking low-dose aspirin daily may reduce the risk of preeclampsia by 53%.

The new screening algorithm gives women more information to help them decide whether to take preventive measures, Bujold said.

"With their personal risk calculated, it's much easier for a woman to make the right decision," he said. "For example, if she chooses to take daily low-dose aspirin, she is much more likely to follow through because it's based on a personalized screening test."

Dr. Sadiya S. Khan, a preventive cardiologist at Northwestern Medicine in Chicago who was not involved in the study, said that predicting risk for term and preterm preeclampsia remains an important goal and a priority for improving maternal health and reducing disparities.

"Since the risks for preeclampsia may be largely influenced by health before pregnancy, the ability of a screening model to be applied in early pregnancy is very helpful and can initiate conversations between the clinician and patient about strategies to optimize heart health," Khan said in the release. "However, challenges remain with implementation of models such as this one that integrate biomarkers that are not routinely assessed and may not be widely available, especially among people in vulnerable populations who are most likely to have the highest risk for preterm preeclampsia."