Significance of amniotic fluid corticosteroid levels in human pregnancies.

Retrospective analysis of 103 samples of amniotic fluid was performed. Twenty-four samples were obtained prior to midtrimester abortion, 31 were from patients who delivered spontaneously, 14 were from patients in whom labor was induced, and the remaining samples were obtained from patients who were delivered by cesarean section. In all normal pregnancies, there was a rising trend in corticosteroid levels in amniotic fluid as the gestation advanced. This was less marked in abnormal pregnancies. There is a suggestive fetal role in initiation of normal spontaneous labor, as reflected by a significant increase in amniotic fluid corticosteroid levels, in patients immediately prior to vaginal delivery as opposed to abdominal delivery. There was a significant correlation between the birthweight of babies born vaginally with the amniotic fluid corticosteroid levels, as compared to the weight of babies born by cesarean section.