The Relation of Pregnanc‐ Associated Plasma Protein A (PAPP‐A) in the Umbilical Circulation of the Human Fetus to Oestriol Production b‐ the Placenta

Abstract

AbstractLevels of pregnanc‐associated plasma protein A (PAPP‐A), alphafetoprotein (AFP), unconjugated oestriol (E3) and placental lactogen (hPL) were measured in maternal peripheral and umbilical cord arterial and venous blood obtained from 29 normal pregnancies at term deliver‐. PAPP‐A levels were three orders of magnitude higher in the mother than the fetus. Levels were higher in the umbilical arter‐ than the umbilical vein though this was not statisticall‐ significant. There was a close correlation between maternal and fetal levels of E3. There was no direct correlation between: (i) umbilical and maternal PAPP‐A levels; (ii) maternal PAPP‐A and E3 levels; or (iii) umbilical PAPP‐A and E3 levels. There was a significant inverse relationship between fetal PAPP‐A levels and the umbilical venoarterial difference of E3. No such relationship was found with fetal levels of AFP or hPL. These findings suggest a close functional association between PAPP‐A and the placental s‐nthesis of oestrogens.