This condition leads to anaphylatoxin generation, contributing to deficient placental vascularization and trophoblast injury.40 Low serum C3 levels and high anti-DNA antibody titers at conception have been linked to poor pregnancy outcomes, such as fetal death and PTB, in SLE pregnancies.28,40 Our study suggests that serum C3 below 0.63 g/L in the first trimester can significantly increase the risk of at least one APO, PE, and PTB. The gene discussed is C3; the disease is systemic lupus erythematosus.