Elevated endothelin levels are associated with increased placental resistance

OBJECTIVE: The purpose of this study was to measure cord blood endothelin-1,2 concentrations in growth-restricted infants with abnormal flow velocity waveforms.STUDY DESIGN: Endothelin-1,2 concentrations were measured by radioimmunoassay in the cord blood of 16 growth-restricted infants with abnormal flow velocity waveforms before delivery, 16 growth-restricted infants with normal flow velocity waveforms before delivery, and 44 appropriately grown infants. Clinical data regarding pregnancy complications and neonatal outcome were collected. RESULTS: The mean endothelin-1,2 concentration in growth-restricted infants with abnormal flow velocity waveforms (50.2 ± 16.4 pg/ml) was significantly higher than in growth-restricted infants with normal flow velocity waveforms (33.3 ± 14.2 pg/ml, p< 0.05) or in appropriately grown infants (25.8 ± 9.7 pg/ml, p< 0.05). Oligohydramnios was also associated with elevated endothelin levels. CONCLUSION: We conclude that endothelin-1,2 concentrations are elevated in growth-restricted infants with abnormal flow velocity waveforms and may play a role in the development of abnormal fetoplacental resistance. (AM J OBSTET GYNECOL 1996;174:1599-604.)