A novel blood assay is now available for expectant individuals in their initial trimester to aid in assessing their susceptibility to preeclampsia, a potentially life-threatening complication during pregnancy.
It represents the sole and pioneering test of its category accessible in the United States, suitable for employment between the 11th and 14th weeks of gestation, for evaluating the risk of preeclampsia prior to the 34th week of pregnancy, as revealed by its manufacturer, Labcorp, on Wednesday. The
initial trimester spans from 0 to 13 weeks of gestation.
Nonetheless, the introduction of this new test does not alter the clinical directives concerning preeclampsia, according to the American College of Obstetricians and Gynecologists (ACOG). Some medical professionals are skeptical about its utility.
Dr. Christopher Zahn, ACOG’s interim CEO and chief of clinical practice and health equity and quality, remarked, “The utility of the LabCorp test in accurately predicting the risk of developing preeclampsia and its appropriateness for all pregnant patients are currently uncertain.”
He further added, “Before a screening test can be effectively applied, there must be an evidence-based intervention to either prevent or mitigate the impact of the disease. Presently, we lack data on how to reduce the risk for a pregnant patient predicted to have preeclampsia based on a blood test early in pregnancy as opposed to clinical factors.”
Preeclampsia, characterized by elevated blood pressure and heightened levels of protein in the urine or other indications of organ impairment, is a pregnancy complication. Typically, the condition manifests after the 20th week of pregnancy—during the second trimester—and if untreated, it can pose serious or fatal consequences for both the mother and the fetus.
While there is no definitive cure for preeclampsia other than delivery of the baby, certain severe cases can be managed with medications such as antihypertensive drugs.
Various factors can predispose an expectant individual to preeclampsia, including advanced maternal age (over 35 years), primiparity, obesity, familial history of preeclampsia, diabetes, hypertension, renal disease, autoimmune disorders, multiple gestations, or assisted reproductive technologies.
The novel screening test assesses any patient’s
risk of preeclampsia by the 34th week of gestation, corresponding to the third trimester, and furnishes a comprehensive risk evaluation with up to 90% sensitivity and 90% specificity, according to Labcorp. Sensitivity denotes the test’s ability to accurately identify high-risk pregnancies, while specificity indicates its ability to correctly identify pregnancies not at high risk.
Physicians who believe their patients might benefit from this screening can discuss the option with them, request the test, and receive results within a few days.
Dr. Brian Caveney, Labcorp’s chief medical and scientific officer, expressed, “This constitutes yet another tool in the arsenal for clinicians in the US and globally to enhance maternal outcomes.” Approximately 1 in 25 pregnancies in the United States is impacted by preeclampsia, making it one of the primary causes of maternal mortality.
Options for screening preeclampsia risk are limited. Prior to the introduction of the new test, at-risk individuals could only undergo screening during the second or third trimester of pregnancy if they exhibited symptoms and were hospitalized, and even that test was introduced just last year.
The new first-trimester test does not serve as a diagnostic tool but as a risk assessment instrument to ascertain whether an individual is more predisposed than average to develop preeclampsia during their current pregnancy, “alongside all the other inquiries your doctor might pose to you during a first-trimester visit,” Caveney explained.
The screening outcomes may prompt “a series of subtle adjustments in the prenatal care provided by your doctor, predicated on the outcomes of this early risk predictor tool,” he stated.
These modifications may involve more frequent doctor visits for monitoring the pregnancy, self-monitoring blood pressure at home at least once a week, avoiding excessive exertion during physical activity or at work, or, if advised by the physician, preemptive intake of low-dose aspirin.
The US Preventive Services Task Force advocates the use of low-dose aspirin as preventive medication after 12 weeks of gestation in individuals at high risk for preeclampsia. However, some individuals and their healthcare providers may be unaware of their high-risk status, particularly during their initial pregnancy.
“At least half or more of cases of preeclampsia are potentially preventable,” remarked Caveney. “Identifying it earlier in the pregnancy increases the likelihood of implementing measures that lead to a healthier pregnancy and, consequently, a healthier delivery.”
The new screening test is categorized as a laboratory-developed test (LDT), thus it does not necessitate approval by the US Food and Drug Administration for execution.
Labcorp is engaged in discussions with health insurance plans to ensure coverage of the test, stated Caveney, noting that the screening assay carries a list price of approximately $240.
How the risk assessment works
Racial inequities also contribute to the risk of preeclampsia. In the US, Black women experience a rate approximately 60% higher than their White counterparts. Moreover, Black women are three times more likely to succumb to pregnancy-related causes than White women, as per data from the US Centers for Disease Control and Prevention (CDC).
"Preeclampsia stands out as a major factor driving the significant gap in maternal outcomes," remarked Caveney. "By prioritizing health equity, we believe that enhanced, evidence-based screening for preeclampsia can potentially mitigate this, alongside various social and healthcare services and improved prenatal care, aiming to enhance pregnancy outcomes both nationally and internationally."
The latest screening technique functions by detecting and quantifying four biomarkers linked to preeclampsia risk.
As outlined by Labcorp, these biomarkers encompass the placental growth factor (PlGF) hormone and pregnancy-associated plasma protein-A (PAPP-A) in the bloodstream, along with a measurement of average arterial pressure and the uterine artery pulsatility index (UtAPI), assessed via ultrasound.
Labcorp suggests that low levels of PlGF and PAPP-A may indicate inadequate placental development and function, while elevated arterial pressure and UtAPI readings may signal heightened blood pressure and reduced uterine artery blood flow.
A 2018 study published in the journal Ultrasound in Obstetrics and Gynecology found that integrating maternal factors with biomarkers, such as mean arterial pressure, UtAPI, PlGF, and PAPP-A measurements, substantially enhances screening performance.
Some doctors raise questions
Not all medical professionals express readiness to recommend the new screening test to their patients.
Dr. Christian Pettker, chief of obstetrics at Yale-New Haven Hospital and a professor at Yale School of Medicine, conveyed his reservations in an email, stating, "The effectiveness of the test in patient management remains unproven, and it's uncertain whether its benefits outweigh potential harms. Its superiority over existing prenatal care standards is not evident."
Pettker added, "I'm unsure if this is suitable for all first-trimester pregnant patients. Perhaps it's most applicable to those with a history of preeclampsia, who already bear a high risk and typically receive specialized monitoring during pregnancy."
"While the test exhibits moderate accuracy in predicting preeclampsia development, the extent of false positive results remains unclear," he cautioned. "The number of patients impacted by a false positive should not be underestimated."
ACOG's Zahn concurred that false positives entail risks. "The assessment of benefits versus risks is crucial with any new screening tool," he emphasized.
Pettker also raised queries regarding the practical implementation of the test for evaluating preeclampsia risk based on biomarkers and the ultrasound assessment of uterine artery blood flow, noting that this isn't a routine procedure for all ultrasound units or physicians and necessitates specific expertise.
Labcorp intends to engage in discussions with physicians and maternal-fetal specialists regarding the test's components, stated Caveney. However, he clarified that the screening test could still be conducted using blood-based biomarkers and regular blood pressure measurements.
"Having more data enhances performance, but it's not mandatory. The test yields optimal results statistically when all relevant data from the physician are available. However, not all obstetrics and gynecology practices or ultrasound facilities routinely offer the capability to calculate the uterine artery pulsatility index," he explained.
"If this data isn't provided, we can still conduct the test and provide a risk assessment, albeit with reduced sensitivity. This lowers the likelihood of accurately predicting preeclampsia risk, but it still outperforms the assessment based solely on traditional maternal risk factors," he added.
Losing a baby ‘should not be the screening’
Eleni Tsigas, the CEO of the Preeclampsia Foundation, highlighted how a screening tool like the new first-trimester test could have had a "significant" impact on her pregnancy journey had it been available during her first pregnancy in 1998.
"My daughter's passing was entirely attributed to a sudden emergency," she recounted.
Tsigas received a preeclampsia diagnosis merely 11 weeks before her due date, leading to the tragic stillbirth of her daughter, Nikonia Evangelia Tsigas.
During that time, she mentioned, she only exhibited one risk factor: being a first-time mother.
"However, losing one's first child should not serve as the primary indicator of high-risk status," Tsigas emphasized. "Many individuals are blindsided during their initial pregnancy by preeclampsia, as they lack any risk factors apart from it being their first."
Following that devastating experience, Tsigas and her spouse welcomed two more children, Jordan and Jonathan. For subsequent pregnancies, she noted, she and her healthcare team maintained heightened awareness of her preeclampsia risk, closely monitoring her health and adhering to low-dose aspirin when advised by her physician.
Tsigas expressed optimism regarding the potential of the newly introduced first-trimester screening test, asserting that if executed effectively, it could prevent unforeseen preeclampsia cases.
However, she stressed the importance of ensuring universal accessibility and equitable distribution of such screening tools to avoid exacerbating existing disparities.
"This raises concerns regarding payer coverage and awareness, ensuring that every woman, irrespective of socioeconomic status, is informed about the availability of this critical information," she emphasized. "If achieved, it could mitigate the disparities observed in maternal and neonatal health outcomes. Tests like these undeniably push the boundaries forward."
