Blood tests play a crucial role in monitoring the health of both the mother and the developing fetus during pregnancy and labor. These tests help detect vital information, including blood type, hemoglobin levels, and the presence of infections or conditions such as anemia, gestational diabetes, and preeclampsia. By identifying potential complications early, healthcare providers can implement appropriate interventions to ensure the safety and well-being of both mother and baby. Additionally, blood tests can help assess the baby’s health and development, guiding decisions related to prenatal care and delivery plans.
A straightforward blood test could aid healthcare providers in pinpointing women in labor who might be at risk of developing preeclampsia, a major contributor to maternal mortality. This promising finding was shared at the ANESTHESIOLOGY® 2024 annual meeting.
According to the Centers for Disease Control and Prevention (CDC), between 5% and 10% of pregnant women experience preeclampsia, which is characterized by sudden high blood pressure and the presence of protein in urine. The CDC highlights that Black women face a 60% higher risk of developing preeclampsia compared to their white counterparts, along with a greater likelihood of experiencing severe complications such as kidney damage. Even though “the prevalence of pre-eclampsia is generally reported as lower in low-income and middle-income countries (LMICs), except sub-Saharan Africa, where the rates are significantly higher”, a report by WHO notes that sub-Saharan Africa has the highest lifetime risk of maternal death, largely due to complications such as preeclampsia and eclampsia. Although preeclampsia can surface as early as the 20th week of pregnancy, this particular study concentrated on identifying women at risk upon their hospital admission during labor.
Researchers discovered a method for doctors to assess a woman’s likelihood of developing preeclampsia by calculating the ratio of two blood proteins—fibrinogen and albumin—obtained from standard blood tests performed when women in labor are admitted to the hospital. Fibrinogen plays a key role in blood clotting and inflammation, while albumin is essential for maintaining fluid balance and transporting hormones, vitamins, and enzymes throughout the body. Preeclampsia can disrupt the levels of both proteins, leading to elevated fibrinogen and decreased albumin, or sometimes both changes.
Currently, there’s no universally accepted normal range for the fibrinogen-to-albumin ratio (FAR), which can vary from 0.05 to 1 or even higher. Elevated FAR values are typically linked to heightened inflammation, infection, or various serious health issues, and greater FAR values indicate increasing concern. This pattern has been consistently observed when using FAR to assess other inflammatory disorders such as rheumatoid arthritis, cardiovascular diseases, and inflammatory bowel disease.
In this study, researchers examined the medical records of 2,629 women who delivered between 2018 and 2024. Among these, 1,819 did not have preeclampsia, 584 had mild preeclampsia symptoms (including blood pressure readings of 140/90 mm Hg or higher without significant organ damage), and 226 experienced severe preeclampsia symptoms (with blood pressure readings of 160/110 mm Hg or higher and indications of organ damage, such as severe headaches, elevated liver enzymes, vision issues, decreased platelet counts, or kidney problems). Findings showed that women with a higher FAR were more likely to develop preeclampsia compared to those with a lower ratio. Specifically, the predicted risk of any degree of preeclampsia was 24% for patients whose FAR was at least 0.1 upon admission, increasing to over 41% when the FAR exceeded 0.3.
When a woman in labor is identified as being at heightened risk for preeclampsia based on her FAR and other clinical indicators—like being over 35 years old or having chronic high blood pressure or obesity—obstetricians and anesthesiologists can implement additional safety measures. This could involve more frequent monitoring of blood pressure or ordering extra lab tests. If a woman’s FAR suggests a risk of severe preeclampsia, an epidural for pain management might be administered earlier in her labor to mitigate risks.
“While FAR has been associated with other inflammatory conditions, its specific application to preeclampsia and preeclampsia with severe symptoms has not been reported in a group this large and racially diverse,” remarked Lucy Shang, B.A., the study’s lead author and a medical student at the Icahn School of Medicine at Mount Sinai in New York. “Our study shows that FAR can be a predictive tool that gives anesthesiologists and obstetricians a new method for assessing a laboring mom’s risk of developing preeclampsia when they are admitted to the hospital.”
She emphasized that while it’s essential to calculate this ratio for all pregnant women, it’s particularly critical for those at increased risk of preeclampsia, such as Black women and those with pre-existing high blood pressure or obesity. “Additional research is needed to determine the exact range of the FAR that would be considered concerning and would be helpful to incorporate into routine prenatal care as a predictive tool for early identification of preeclampsia,” she added.
This report from the ANESTHESIOLOGY® 2024 annual meeting has been published on the website of the American Society of Anesthesiologists.
