Blood Levels of 17-Hydroxycorticosteroids (17-OHCS) During Labor of Human Pregnancy.

Abstract
1. Blood levels of 17-OHCS were studied at intervals during parturition in normal pregnancy. 2. Early in labor, a rise in levels above those found in late pregnancy was noted, with further rise between first and second stages. These high levels were maintained until after the end of 3rd stage. In most cases studied, levels were still well above normal on 4th or 6th postpartum day. 3. There seems to be a relation between length of labor and rise in plasma 17-OHCS. Labors of longer than 6 hours deviation were accompanied by high levels of these hormones. 4. Maximum values observed in labor approached those noted after exogenous ACTH stimulation during late pregnancy, indicating nearly maximal output of these hormones by the adrenal cortex. 5. The mechanisms by which labor stimulated the maternal pituitary gland have been discussed.