HEMODYNAMIC ADAPTATIONS AT BIRTH AND NEONATES DELIVERED VAGINALLY ANDBY CESAREAN-SECTION

In order to assess the possible influence of differences in delivery m ode on cardiovascular adaptation at birth, we measured left ventricula r output and its regional distribution in the major organs sequentiall y using an echographic technique during the first 96 h of life. We stu died 27 normal newborns, of whom 15 were delivered vaginally and 12 by cesarean section, We also measured umbilical arterial and venous cate cholamine concentrations. The umbilical arterial epinephrine and norep inephrine concentrations in the infants delivered vaginally were signi ficantly greater than those in the infants delivered by cesarean secti on (epinephrine 1,195 +/- 208 vs, 565 +/- 81 pg/ml, p < 0.05; norepine phrine 11,832 +/- 3,819 vs. 5,153 +/- 1,400 pg/ml, p < 0.05), The left ventricular output and its regional distribution showed a similar pat tern in the two groups, and there were no significant differences betw een them. These results indicate that the capacity of infants delivere d by cesarean section to tolerate cardiovascular changes during the ea rly neonatal period is comparable to that in infants delivered vaginal ly, even though there are significant differences in the catecholamine surge between these groups.