Relationship between the cortisol levels in umbilical cord blood and neonatal RDS/TTN in twin pregnancies.

Objective: Twin neonates have a higher risk of respiratory complications, such as respiratory distress syndrome (RDS) and transient tachypnea of the newborn (TTN), than singleton neonates. The purpose of this study was to evaluate the relationship between the cortisol levels in the umbilical cord and neonatal RDS/TTN in twin pregnancies.
Methods: We analyzed data obtained from 106 neonates (53 twin pairs), comprising 33 dichorionic twin (DCT) and 20 monochorionic twin (MCT) gestations. All infants were delivered via scheduled cesarean section without labor. We measured the cortisol levels in umbilical vein blood using enzyme-linked immunosorbent assay.
Results: The cortisol levels in the umbilical vein were significantly lower in the RDS/TTN group than in the no RDS/TTN group (p = 0.004). The umbilical cortisol levels in the TTN group were between the values observed in the RDS group and no RDS/TTN group. We subsequently analyzed the cut-off cortisol values for RDS/TTN and observed higher accuracy in the DCTs than in the MCTs.
Conclusions: Neonates who develop RDS/TTN have significantly lower cortisol levels in the umbilical cord at birth than no RDS/TTN neonates in twin pregnancies. When applying these data in clinical practice, physicians should pay attention to differences based on chorionicity.