APPARENT SECRETION OF PROGESTERONE BY HUMAN AND GOAT FETUSES1

Abstract

Blood samples were drawn from unbilical arteries and veins in 25 human pregnancies at or near term and in 3 goat pregnancies between the 116th and 134th day. Plasmas were bio-assayed for progesterone equivalents. In 16 of the human pairs and in 3 of the caprine pairs the progesterone equivalent level was appreviably higher in the plasma from the umbilical artery than in that from the corresponding umbilical vein. This is interpreted as indicating production of progesterone by the fetus and removal of the hormone from the umbilical blood by the placenta.