Prostaglandin biosynthesis in the umbilical artery and its relation to fetal growth

Arachidonic acid metabolites were investigated in umbilical arteries of 16 normal pregnancies. Several prostaglandins (PGs) and hydroxyacids were synthesized by the umbilical artery. Prostaglandin I2, PGF2 alpha, PGE2 and PGD2 were found in the products, and PGI2 was the most abundant metabolite in the umbilical artery. The conversion rate of PGI2 from arachidonic acid is strongly correlated with the body weight of the baby (correlation coefficient: 0.621) and with the weight of the placenta (correlation coefficient: 0.668). PGI2 is known to be a strong vasodilator and anticoagulant, and is known to increase blood circulation. We therefore conclude that the PGI2-synthetic activity of the umbilical artery is strongly related to feto-placental blood flow and hence to fetal growth.