Fetal circulatory responses during maternal bleeding

Abstract

The purpose of this study was to investigate the fetal circulatory responses during maternal hemorrhage. Five pregnant goats with fetuses with a mean gestational age of 132 +/- 2 days were used. The maternal blood was withdrawn at 350 ml/h for 2 hours (e.g. 700 ml, 11.9 ml/kg maternal weight) and reinfused at the same speed. During maternal bleeding, maternal arterial pressure (MAP) gradually decreased. As a result of this maternal hypotension, fetal arterial pO2 and pH decreased, and PCO2 increased. After the reinfusion, fetal pO2 recovered but pH and PCO2 did not recover. Fetal arterial pressure (FAP) increased and 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 bleeding. There were significant positive correlation between AVP concentration and FAP, and negative correlation between AVP and FHR during maternal bleeding. Therefore, we concluded that 700 ml maternal bleeding for 2 hours resulted the decrease in fetal pH, pO2, and FHR, and increase in PCO2, FAP, and AVP concentration. Fetal pH, PCO2, and AVP did not return to the control level in spite of reinfusion.

Fetal Heart Rate Patterns in Monochorionic Twins Following Acute Twin-Twin Transfusion

“…One showed tachycardia, and the other showed normocardia. In some animals, there have been some observations in various fetal cardiovascular responses to fetal blood loss [ 7 , 8 ]. Yoshihara et al [ 7 ] observed that fetal heart rate did not change measurably during 40 ml per 2 hours of fetal hemorrhage in pregnant goats near term.…”

“…In some animals, there have been some observations in various fetal cardiovascular responses to fetal blood loss [ 7 , 8 ]. Yoshihara et al [ 7 ] observed that fetal heart rate did not change measurably during 40 ml per 2 hours of fetal hemorrhage in pregnant goats near term. Brace and Cheung [ 8 ] observed that the heart rate in fetal sheep was elevated by an average of 2 bpm at 3 to 5 hours after the fetal hemorrhage of 30% of their initial blood volume although it did not change measurably during the hemorrhage.…”

“…Brace and Cheung [ 8 ] observed that the heart rate in fetal sheep was elevated by an average of 2 bpm at 3 to 5 hours after the fetal hemorrhage of 30% of their initial blood volume although it did not change measurably during the hemorrhage. These changes have been observed to be due to the changes in fetal plasma renin activity, arginine vasopressin, and norepinephrine following fetal blood loss [ 7 , 8 ]. Therefore, the differences in changes of fetal heart rate in the donor twins of acute twin-twin transfusion may be resulted from the differences in amount of transfusion and elapsed time.…”