Thrombocytopenia may increase the risk of preeclampsia in pregnant women with COVID-19

By Dr. Sanchari Sinha Dutta, Ph.D.Nov 7 2022Reviewed by Aimee Molineux

A study published in Reproductive BioMedicine Online describes that coronavirus disease 2019 (COVID-19) may increase the risk of preeclampsia in pregnant women with low blood platelet count (thrombocytopenia).

Background

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been found to have the most adverse impact on elderly people, immunocompromised patients, and people with pre-existing health conditions. A few studies have also suggested that the disease might have a negative health impact during pregnancy.

During pregnancy, the body experiences certain physiological changes, including increased blood volume, heart rate, blood clotting factors, oxygen consumption and reduced lung capacity, blood platelet count, and cellular immunity. All these factors collectively can make a pregnant woman more susceptible to severe COVID-19.   

A reduction in blood platelet count (thrombocytopenia) increases the risk of severe COVID-19, hospitalization, and mortality in non-pregnant women. Preeclampsia is a high blood pressure disorder that can occur during pregnancy. In pregnant women, thrombocytopenia is considered the initial sign of preeclampsia, and both thrombocytopenia and preeclampsia correlate significantly with disease severity.

In the current study, scientists have investigated the prevalence and clinical significance of thrombocytopenia in pregnant women with COVID-19.

Study design

The study was conducted on 153 pregnant women with laboratory-confirmed COVID-19. A platelet count of less than 150,000 per microliter of blood was considered the clinical criteria for diagnosing thrombocytopenia.

Important observations

The prevalence of thrombocytopenia was estimated to be 12% in pregnant women with COVID-19. The condition is more prevalent in comparatively older women (on average, three years older). About 7-times higher risk of thrombocytopenia was observed in smokers than in non-smokers.

Regarding other risk factors, the blood group of pregnant women exhibited a significant association with thrombocytopenia. About 17-times higher risk of thrombocytopenia was observed in pregnant women with Rh- blood group B compared to other blood groups.

A significant correlation was also observed between thrombocytopenia and preeclampsia. Specifically, pregnant women with thrombocytopenia and COVID-19 had a 16-times higher risk of developing preeclampsia.   

Thrombocytopenia observed in pregnant women was characterized by a steady and significant reduction in blood platelet count from the first to the third trimester. In pregnant women with low hemoglobin levels during infection, a significant induction in platelet count was observed in the second and third trimesters.

A significant reduction in platelet count was observed in pregnant women with a postpartum hemorrhage. A significant negative correlation was observed between platelet count at delivery and maternal-activated partial thromboplastin time (blood coagulation test). A similar correlation was also observed for prothrombin time (another blood coagulation test). 

Study significance

The study highlights that the prevalence of thrombocytopenia is similar in pregnant women with and without COVID-19. Thus, scientists believe SARS-CoV-2 infection is not a risk factor for reduced blood platelet count observed during pregnancy.

The study identifies certain risk factors for thrombocytopenia in pregnant women with COVID-19. These risk factors include increased age, smoking, and having an Rh- blood group B.

Another vital finding of the study is that thrombocytopenia can significantly increase (16-fold) the risk of preeclampsia in pregnant women with COVID-19. Moreover, the study suggests that SARS-CoV-2 might negatively affect the fetus's well-being during pregnancy. However, the scientists mention that more research is needed to establish this finding conclusively.

Overall, the study provides important observations on the prevalence and clinical significance of low blood platelet count in pregnant women with COVID-19. This information could help develop potential preventive and therapeutic interventions to reduce pregnancy-related complications.