Amniotic fluid cortisol concentrations in normal labor, premature labor, and postmature pregnancy.

Amniotic fluid cortisol concentration was measured in 61 gravidas during the third trimester prior to onset of labor. These patients had had normal prenatal courses and served as controls. Cortisol values obtained were compared with those of 1) gravidas with prolonged pregnancy (greater than 42 weeks) who delivered post-mature neonates (N=6), 2) gravidas in spontaneous term labor (N = 10), and 3) gravidas in premature labor (N=10). The mean level of amniotic fluid cortisol (+/-SD) found in those women with premature labor was significantly elevated compared to control values (P less than 0.05). Levels recorded in premature labor patients were in the same range as in the term spontaneous labor group (3.7+/-2.5 vs. 2.7+/-1.5; P greater than 0.3). No difference was found between the spontaneous labor group or the postmature group and their respective controls.