BLOOD-LEVELS OF VASOACTIVE INTESTINAL POLYPEPTIDE IN NORMAL AND GROWTH-RETARDED FETUSES - RELATIONSHIP WITH ACID-BASE AND HEMODYNAMIC STATUS

The objectives of this study were (1) to detect vasoactive intestinal polypeptide in fetal blood obtained by cordocentesis (2) to examine po ssible changes in growth retarded fetuses and to establish relationshi ps between its levels and fetal blood acid-base status as well as feta l haemodynamics as assessed by Doppler ultrasonography, Vasoactive int estinal polypeptide was measured in umbilical vein blood obtained at c ordocentesis in 12 growth retarded fetuses and in 13 control fetuses. Umbilical vein pH and PO2 values were determined in all the cases. Bef ore the procedure, Doppler indices were calculated from umbilical arte ry, middle cerebral artery, renal artery, cardiac outflow tracts and i nferior vena cava. Simple and multiple stepwise regression analysis we re performed to examine the relationships between Doppler indices, aci d-base status and vasoactive intestinal polypeptide levels. In control fetuses, vasoactive intestinal polypeptide was always detectable in c ord blood and its levels did not change with gestational age. In growt h retarded fetuses, vasoactive intestinal polypeptide levels were high er and significantly related to umbilical vein PO2 levels. Pulsatility Index in umbilical artery, middle cerebral artery and renal artery, w hile no relationship was found with umbilical vein pH, cardiac and ven ous Doppler indices. Stepwise multiple regression demonstrated middle cerebral artery Pulsatility Index to be the best explanatory variable for vasoactive intestinal polypeptide levels. In conclusion, vasoactiv e intestinal polypeptide blood levels are increased in growth retarded fetuses and this increase is inversely related to the Doppler measure d impedance to flow in middle cerebral artery.