Pregnancy zone protein (PZP) is a protein which in humans is encoded by the PZP gene on chromosome 12. PZP is part of the alpha-2 globulin family of proteins. It is often associated with pregnancy, during which it can be the most abundant amongst the plasma proteins. PZP is believed to play a role in immune-regulation during pregnancy, however many aspects of its mechanism, function and structure are yet to be determined. Recent research has largely focused on determining how dysregulated PZP levels can act as a markers of various diseases.