Here we demonstrate that regulation of the Complement (C′) components of the immune
system is an ancient and conserved feature of mammalian pregnancy. Transcript levels
were reduced for complement components C3 and C4 throughout pregnancy in a marsupial,
Monodelphis domestica. Downstream C′ component transcripts were significantly less
abundant relative to non-pregnant controls at the start of pregnancy but increased during
late pregnancy, in some cases peaking close to parturition. These results are consistent with …