Preeclampsia is one of the most feared and most mysterious complications of pregnancy in the modern age. Preeclampsia can involve elevated blood pressure, protein in the urine, and even end organ damage (like the liver or kidneys) during pregnancy. It can develop into seizures, called eclampsia, a complication humans have recognized for ages. Preeclampsia is not just dangerous for expecting mothers; it has been linked to small-for-gestational-age infants and fetal and neonatal death. The criteria for diagnosing preeclampsia are ever-changing, and every month new studies dig deeper into the quest to understand why some women develop this complication. This October, the Grey Journal published a new study about predicting who will develop preeclampsia by a group of physicians led by Dr. Bahado-Singh of William Beaumont Health in Michigan, along with colleagues in London and Canada.
Dr. Bahado-Singh and his Canadian colleagues tried to predict the future by using blood draws & ultrasounds in the first trimester to predict who will develop early onset preeclampsia. They used samples from 30 women who went on to develop early onset preeclampsia and 65 women without preeclampsia to hunt down metabolic markers associated with preeclampsia. They then tested out their theories using another set of blood samples and ultrasounds from 20 women who eventually developed preeclampsia and 43 controls.
The authors used a slew of metabolites from the blood samples in their prediction equation. Two interesting newly identified metabolites were arginine and 2-hydroxybutyrate. Using blood samples alone to predict preeclampsia was only about 75% sensitive and specific. If you add in ultrasound results for Doppler uterine artery pulsatility index, which is high in women who go on to develop preeclampsia, then your predictive powers increase. Using the metabolic analysis of the first trimester blood samples and the ultrasound pulsatility index, sensitivity and specificity for predicting early onset preeclampsia increased to about 90%.
The authors explain that these two new metabolites, arginine and 2-hydroxybutyrate, make sense as metabolic markers for preeclampsia. Arginine can yield nitric oxide, which dilates blood vessels. If arginine and thus nitric oxide is low, it is theorized that blood vessels will be more constricted, which would lead to high blood pressure, as we see in preeclampsia. 2-hydroxybutyrate has been tied to insulin resistance and problems with regulating glucose.
Perhaps in the future, we will be able to use these metabolic and ultrasound predictors to identify women most at risk for early-onset preeclampsia. If so, doctors could try to decrease their risk of developing preeclampsia by giving them aspirin during their pregnancy.