Distribution of placental protein 14 in tissues and body fluids during pregnancy

Abstract
Summary. Placental protein 14 (PP14) levels were measured in serum samples from non‐pregnant and pregnant women. amniotic fluid, cord blood, and extracts of placenta, decidua and fetal membranes. The levels were low (15–40 μg/l) in serum of non‐pregnant women. In four pregnancies following in‐vitro fertilization, the serum PP14 levels started to rise 2–12 days after embryo replacement. In normal pregnancy, the highest serum PP14 concentrations (up to 2200 μg/l) were detected between 6 and 12 weeks. After 16 weeks the level decreased and plateaued at 24 weeks to around 200 μg/l. In amniotic fluid, the highest PP14 levels (232 mg/l) were found between 12 and 20 weeks, being considerably higher than those in maternal serum throughout pregnancy. In cord blood, the levels were low (15–22 μg/l) or undetectable. In early pregnancy decidua. the PP14 content was higher (41–160 mg/g total protein) than in late pregnancy decidua (60–2700 μg/g total protein). In amnion and chorion laeve, the PP14 concentration varied from 50 to 750 and 50 to 1000 μg/g protein, respectively. Early pregnancy placenta contained 0‐25‐15 mg/g and late pregnancy placenta 3–430 μg/g protein of PP14. These results show that the levels of PP14 in pregnancy serum have a similar profile to hCG, but in contrast to other placental proteins, the amniotic fluid PP14 levels are remarkably high. This may be explained by suggesting that decidua is a source of PP14.