[Excretion of 7 estrogens during last days of human pregnancy]

The excretion of seven urinary estrogens was studied during the last two or three weeks of five normal pregnant women. A study of the urinary excretion curves demonstrated that 16 alpha-hydroxyestrone and 16-oxo-estradiol followed the same pattern with the particularity of presenting two excretion peaks which were persistently observed on the 8th or 7th day prior to delivery for the first one, and around the 4th or 3rd day prior to delivery for the second one. It is possible that there is a relation between this phenomenon and the onset of delivery.