Cord blood cortisol levels and respiratory distress syndrome

Cord blood cortisol levels were analyzed in 121 neonates, using a "Coat a Count" RIA kit. Forty two appropriate for gestation age (AGA) preterms < 34 weeks who had not received antenatal dexamethasone constituted Group A, 32 AGA preterms < 34 weeks gestation who had received dexamethasone antenatally comprised Group B, while Group C consisted of 47 term normal neonates. Cortisol levels were compared in these 3 groups and correlated to the development of respiratory distress syndrome (RDS). It was observed tht preterms (Groups A and B) had significantly (p < 0.005) lower levels (8.45 +/- 6.31 micrograms/dl) compared to term neonates (11.67 +/- 4.68 micrograms/dl). Antenatal dexamethasone therapy did not significantly alter cortisol levels within the group of preterms. There was a significant difference (p < 0.02) in cortisol levels between those preterms who developed RDS (5.41 +/- 4.91 micrograms/dl) and those who did not (9.58 +/- 6.45 micrograms/dl). Preterms (Grous A and B) who did not develop RDS had cortisol levels comparable to term neonates. There was a significant reduction in the incidence of RDS (p < 0.05) in preterms who had received antenatal dexamethasone. Cord blood cortisol levels < or = 7 micrograms/dl had a positive predictive accuracy of 36.59% and negative predictive accuracy of 93.75% in predicting onset of RDS.