<unk>  <unk>  is a<unk>  protein produced by<unk>  cells. It is found at the interface of the chorion and the decidua (between the<unk>  sac and the uterine lining). It can be thought of as an adhesive or "biological glue" that binds the<unk>  sac to the uterine lining.
Fetal fibronectin
Hyperforin
Lipoprotein-X
Von Willebrand factor
Platelet membrane glycoprotein
Fetal hemoglobin
PULHES Factor
Glycoprotein IX