C3 and systemic lupus erythematosus: Therefore, it seems that C3 and C4 levels may or may not be predictive for poor pregnancy outcomes such as preterm pre-eclampsia, spontaneous abortion, premature birth, and stillbirth; likewise, Ba, and Bb fragments and sC5b-9 MAC among lupus pregnancy with positive antiphospholipid antibodies are sensitive indicators of excessive complement activation and predictive for not only for lupus flare but also for pregnancy complications (the PROMISSE study) [1,2,20,21,44,50,53].