Successful pregnancy ensures the continuation of our species. Pregnancy is a time during which the mother’s physiology is uniquely altered to accommodate the growth and development of the fetus. Maternal immune modulation is central to this process. Rather than a state of mere immune suppression it is now apparent that pregnancy is facilitated by a complex interplay of cytokine pathways. Regulated inflammation is emerging as being key to the initiation and maintenance of pregnancy. This presentation will outline how the processes that are necessary for normal pregnancy and highlight how their dysregulation may lead to pregnancy complications such a pre-eclampsia. The contribution of the placenta to maternal immune regulation will be highlighted.