FETAL CIRCULATORY RESPONSES DURING MATERNAL BLEEDING

The purpose of this study was to investigate the fetal circulatory res ponses during maternal hemorrhage. Five pregnant goats with fetuses wi th a mean gestational age of 132 +/- 2 days were used. The maternal bl ood was withdrawn at 350 ml/h for 2 hours (e.g. 700 ml, 11.9 ml/kg mat ernal weight) and reinfused at the same speed. During maternal bleedin g, maternal arterial pressure (MAP) gradually decreased. As a result o f this maternal hypotension, fetal arterial pO(2) and pH decreased, an d pCO(2) increased. After the reinfusion, fetal pO(2) recovered but pH and pCO(2) did not recover. Fetal arterial pressure (FAP) increased a nd heart rate (FHR) decreased during maternal bleeding and returned to the control level, after the reinfusion. Fetal arginine vasopressin ( AVP) concentration increased to 401.2 +/- 318.5 pg/ml at the maximum b leeding. There were significant positive correlation between AVP conce ntration and FAP, and negative correlation between AVP and FHR during maternal bleeding. Therefore, we concluded that 700 ml maternal bleedi ng for 2 hours resulted the decrease in fetal pH, pO(2), and FHR, and increase in pCO(2), FAP, and AVP concentration. Fetal pH, pCO(2), and AVP did not returned to the control level in spite of the reinfusion.