Changes in plasma proteins during pregnancy

Changes in maternal plasma proteins during pregnancy are now well documented. These changes may be quantitative, as seen in the elec-trophoretically separated fractions of serum and in the various binding globulins; or they may be represented by the appearance of a protein which is present only in the serum of pregnant women. These include the placen tal isoenzym e of alkaline phosphatase, oxytocinase, hum an chorionic gonadotropin and the “ pregnancy-associated plasma proteins. ” Other con stituents, such as a-fetoprotein, salivary amylase, prolactin and the proteins of the “pregnancy zone, ” which are present in small quantities in non pregnant women as well as in men, show a substantial increase in concen tration in the maternal circulation during pregnancy. An important factor in the etiology of protein changes is the effect of hormones, especially estro gen, on the synthesis and degradation of these proteins. W hile certain quantitative changes such as those seen in hormone b ind ing proteins may in terfere w ith diagnostic procedures, a num ber of pregnancy-associated changes in protein composition of the m aternal circu lation may be used to follow the course of pregnancy by monitoring placen tal function as well as fetal maturity and well being