Pregnancy-specific beta-1 glycoproteins (PSGs) are a group of proteins that are produced by the placenta during pregnancy and can be found in the mother's bloodstream. They are also known as trophoblast-derived beta-1 glycoproteins. These proteins are part of the larger family of immunoglobulins, which are proteins that play a role in the immune system.

Proteiner som produceras av den gravida kvinnans organ eller moderkaka. Sådana proteiner kan vara graviditetsspecifika (dvs att de endast förekommer under graviditeten) eller graviditetsassocierade (kan förekomma antingen under graviditeten eller i samband med t ex hormonbehandling eller vissa tumörsjukdomar).