Abstract

AIM To compare plasma endothelin-1 (ET-1) concentrations in preterm neonates from pre-eclamptic and normal mothers; and to evaluate whether ET-1 has a role in altered arterial blood flow velocity.

METHODS Umbilical arterial blood and neonatal arterial blood were sampled on days 1 and 3 for gas analysis and measurement of plasma ET-1. Doppler ultrasonography of the middle cerebral, renal, and superior mesenteric arteries (SMA) was performed.

RESULTS Neonates in the pre-eclampsia (n=18) and control (n=18) groups had mean (SD) gestational ages of 31.1 (2.5) weeks and 30.4 (2.1) weeks; their birthweights were 1432 (SD 676) g and 1692 (SD 500) g, respectively. In the pre-eclampsia group mean umbilical arterial PO₂ was lower—1.88 (0.75) kPa compared with 3.27 (1.41) kPa (p < 0.01)—and mean plasma ET-1 concentration was higher in the umbilical artery—40.6 (SD 15.0) compared with 30.5 (SD 13.8) pg/ml (p=0.04) and day 1 blood—54.9 (35.0) pg/ml compared with 33.6 (14.6) pg/ml (p=0.03). Middle cerebral artery peak systolic velocity was higher and SMA time averaged, peak systolic, and mean peak velocities were lower in the pre-eclampsia group. SMA time averaged velocity was inversely related to plasma ET-1 concentration.

CONCLUSION The association between increased production of ET-1 and reduction in SMA time averaged velocity suggests a possible mechanism for hypoperfusion of the intestinal wall in neonates.