Systemic inflammation indices generated from first-trimester blood tests can be potential biomarkers for predicting preeclampsia

Preeclampsia is a leading cause of maternal and neonatal morbidity and mortality, affecting 3 to 8% of pregnancies. Currently, no clinically useful predictive biomarker exists. Preeclampsia is characterised by systemic inflammatory responses that may be triggered by placental materials released into the maternal circulation, leading to an overly active maternal immune system. Recently, systemic inflammation indices have been used as indicators of inflammation in various diseases. Here, we investigated whether systemic inflammation indices derived from peripheral blood tests in the first trimester could serve as potential predictors of preeclampsia. Blood samples, ranging from 6 to 12 weeks, were collected from 109 women who later developed preeclampsia and 177 women who did not develop any complications. The counts of white blood cells, neutrophils, lymphocytes, monocytes, eosinophils, basophils, and platelets were obtained, and systemic inflammation indices, including the systemic immune inflammation index (SII), the systemic inflammation response index (SIRI), the neutrophil-to-lymphocyte ratio (NLR), and the pan-immune inflammation value (PIV), were calculated. Significantly higher counts of white blood cells, neutrophils, lymphocytes, and monocytes, but not eosinophils and basophils, were observed in women who later developed preeclampsia (p < 0.001). Additionally, all four indices were significantly elevated in women who later developed preeclampsia (p < 0.001). The increased indices were primarily associated with late-onset preeclampsia. No significant differences in these indices were observed between women who developed preeclampsia with or without severe features. Our study demonstrates that systemic inflammation indices derived from first-trimester blood tests may serve as additional predictors for preeclampsia when combined with other reported biomarkers.