Variations of the excretion curves of seven urinary estrogens during late pregnancy

The variations of the excretion curves of 7 different urinary estrogens have been studied by gas chromatography in 15 uncomplicated pregnancies during the last quarter or the last 2 wk before term. Normal values are indicated. When the pattern of each pregnancy is studied separately, the variations observed in estriol percentages are contrary to the variations of 16α-hydroxyestrone and of 16-oxoestradiol but the sum of these percentages is always constant in the last quarter of pregnancy. In the last days prior term, 16α-hydroxyestrone and 16-oxoestradiol are the only estrogens reaching, as a rule, two peak values.