Estetrol and utero-placental flow after progesterone load.

: On the basis of recent demonstration in animals of the effect of some hormones on uteroplacental flow, the Authors examined the response of plasmatic Estetrol (15 alpha-hydroxy-estriol) after the administration of progesterone to pregnant women with low Estrogen values. The increase of this compound was related to an improvement of placental function, probably dependent on an increase of available O2, and therefore on uterine blood flow. This can justify a progesterone treatment in such pregnancies.