Origin of Estrogen in Women Pregnant with an Anencephalic Fetus*

Abstract

The genesis of estrogen in 4 patients pregnant with an anencephalic fetus has been studied. The results indicate that the bulk (50 to 100%) of the estrogen produced by these subjects was derived from the placental utilization of dehydroisoandrosterone sulfate circulating in the maternal plasma. In addition, evidence is presented for the synthesis of estriol from dehydroisoandrosterone sulfate through a pathway that does not involve estrone or estradiol. The results of this study further indicate that induced changes in the level of production of precursor, dehydroisoandrosterone sulfate, effected similar changes in the level of production of estrogen. On the basis of these results it is suggested that the placenta relies heavily, perhaps exclusively, upon externally supplied C19 precursors for estrogen synthesis, and that these precursors may arise in either the maternal or fetal compartment.