[8] 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.

[9][10] Recent research has largely focused on determining how dysregulated PZP levels can act as a markers of various diseases.

[12] This was a result of an experimental process using starch gel zone-electrophoresis, which detected a protein band in the sera of 10% of the studied women in late pregnancy and after delivery.

[19][15] In healthy adults and children in normal conditions, both male and female, PZP itself has been found to be present in low levels.

[20] The amount of PZP in the plasma of healthy people in normal conditions has been identified as <0.03 mg/mL while for pregnant women this can rise to be at concentrations of 0.5 - 3.0 mg/mL.

[24] Pregnancy zone proteins (PZPs) exist in the functionally active form as homodimers of 360 kDa molecular weights.

[25][15] The bait region has numerous protease cleavage sites, while the binding domain is for low density lipoprotein receptor-related protein (LRP).

[15] A study of the bait domain has shown a rare polymorphism occurring, with either Valine or Methionine being at the sixth amino acid position.

[25] The minimal knowledge available about the PZP multi-domain fold allows only an approximation of its tertiary structure based on that of a transformed α2M at 4.3 Å resolution.

[30] Over many years PZP has been classified as a protease inhibitor, however, as was observed in a paper in 2016, more recently, the suggestion of the roles of a T-helper cell modulator and/or an extracellular chaperone has been made.

[16] In contrast to this, while PZP and PAI-2 display no obvious structural similarities, they show functional commonalities and complementary activity in extracellular fluids.

[27] Amy R. Wyatt et al. observe that there is no substantial evidence to support suggestions of PZP being involved in the control intracellular protease activities including those of chymotrypsin-like enzymes.

Furthermore, in postmortem examinations, the immunoreactivity of PZP in the cortex of AD patients was specifically seen in the microglial cells associated with senile plaques, and in some neurons.

[38] PZP levels were found to not differ significantly in breast cancer patients, thus deeming this protein ineligible as a biomarker of this disease.

PZP was shown to be one the proteins determined as potential biomarkers of Poor Ovarian Responder (POR) in IVF.

[42] The synthetic estrogen ethinylestradiol (EE) shows strongly disproportionate effect on PZP and SHBG levels compared to natural estradiol.