Assessment of biomarkers indicating activation of the complement system in pregnant women with fetal growth restriction

Abstract

Aims: To compare serum levels of sC5b-9, C3, C4, C1-INH, and CH50, which are indicators of complement system activation and regulatory processes, in pregnant women with and without fetal growth restriction (FGR). Methods: This study enrolled eighty-six women with gestational age between 24 and 36 weeks. Maternal blood samples were obtained from 43 patients diagnosed with FGR and 43 from healthy pregnancies. Serum complement levels were measured using commercially available ELISA kits according to the manufacturer’s instructions (SunRed, China). Results: When the levels of complement activation biomarkers of pregnancies with FGR were compared with those of healthy pregnancies, the C1est level was significantly higher, C4 and CH50 levels were slightly lower, and Sc5b9 and C3 levels were similar. Conclusion: While the exact role of complement activation in FGR remains fully elucidated, the elevated levels of C1-INH in women with FGR suggest a compensatory mechanism to mitigate thrombus formation and inflammation. This adaptive response may be a potential therapeutic target for improving placental function and pregnancy outcomes.