Blood test could aid in the differential diagnosis of preeclampsia and COVID-19 in pregnant women

Reviewed by Emily Henderson, B.Sc.Apr 27 2022

Pregnancy brings deep changes in women's physiology, especially regarding her blood system. The placenta is the organ which ensures an efficient communication between the mother and the baby. This organ grows quickly and links a significant quantity of mother's blood supply to the fetus'. Thus, placenta has a relevant impact on blood pressure and it may turn into a source of cardiovascular risk.

Preeclampsia is an inflammatory condition that appears during pregnancy and whose cause is still unknown. This condition is characterized by high blood pressure combined with organ dysfunctions, such as renal and liver failure. Should preeclampsia not be early diagnosed, it can lead to serious complications for the mother and the baby. Induced delivery and placenta removal are currently the only solution for this condition.

First cases of COVID-19, caused by SARS-CoV-2 infection, appear at beginning of 2020. COVID-19 may cause severe illness on vulnerable population, including pregnant women. The clinical manifestation of this severe infection goes beyond a dysfunction of the respiratory system and can have similarities with preeclampsia. These similarities may cause errors in the treatment of the patients, as they have different needs: in preeclampsia we prioritize the delivery of the baby and for COVID-19 we focus on the recovery of the disease.

In both cases we observe a disruption of the normal function of the endothelium, which is the inner lining of the blood vessels and is partly responsible for the blood pressure.

Dr. Marta Palomo from the Josep Carreras Leukaemia Research Institute, together with Dr. Lina Youssef, Dr. Francesca Crovetto and Dr. Fàtima Crispi, from BCNatal (Hospital Clínic and Hospital Sant Joan de Déu) and the Fetal and perinatal medicine group of IDIBAPS, and under the supervision of Dr. Maribel Díaz-Ricart, head of the Hemotherapy and Hemostasis group of Clínic-IDIBAPS, questioned the extent to which Preeclampsia and COVID-19 share biological characteristics. They assessed indicators of endothelial disfunction, blood clotting, angiogenesis and immune function from blood of pregnant women with Preeclampsia or COVID-19 and compared them with of healthy pregnant women's.

The results of this study have been recently published in the international renowned American Journal of Obstetrics and Gynecology, considered as the most important review in gynecology. In the publication, the research team achieves to differentiate Preeclampsia from severe COVID-19 thanks to the strong and reproducible differences in the panel of indicators, being angiogenesis (sFlt-1, Ang2 and P1GF), blood clotting (antigen vWF) and endothelial damage (VCAM-1 and sTNFRI) the most patent.

The study also shows that there are shared elements between both pathologies such as the activation of the complement system, an important part of the immune system, even if the alterations caused by COVID-19 are less significant than the ones caused by Preeclampsia.

These outcomes are a further step in Preeclampsia characterization, a little-known pregnancy-related disease but main responsible for maternal and perinatal mortality in the world and premature births. These results are also medically relevant, as they offer diagnostic tools which allow to distinguish Preeclampsia from COVID-19 and help in their clinical management and treatment.

This study has been carried out in the framework of the Project "Analysis of the complement system in severe preeclampsia and Hellp syndrome as therapeutic target" funded by the telethon La Marató of TV3 in its 2019 edition dedicated to rare diseases.