The Effect of Oxygen Ventilation and a Vasodilator on Uterine Perfusion, Foetal Oxygen and Acid‐Base Balance

Abstract

Uterine perfusion, the po2 in maternal ear capillary blood, the po2 and pH in portio blood, and the po2 PH, BE and pco2 in blood from the foetal scalp were investigated in 50 normal women in the 36th or subsequent weeks of pregnancy, women were given either oxygen ventilation, xanthinol nicotinate (Complaminr`), or oxygen ventilation in conjunction with this drug. Uterine perfusion decreased in all groups, the greatest fall being in the group ventilated with 100% oxygen. The po2 rose in all groups given oxygen. The smallest rise was noted in foetal blood. The remaining changes in blood chemistry were very small.

Reducing stillbirths: interventions during labour

“…Interestingly, while there appeared to be an impact on perinatal mortality, maternal hyperoxygenation did not appear to improve fetal growth. We classify maternal hyperoxygenation as having some evidence of benefit in reducing perinatal mortality given the promising findings of the Cochrane review on this subject, but suggest that this intervention not be included in programs until confirmatory results become available, as some prior studies have suggested that maternal hyperoxygenation may inadvertently reduce uterine blood flow, and that long-term oxygen therapy may be associated with maternal pulmonary dysfunction [ 121 - 123 ].…”

Effects of maternal hyperoxia with and without normocapnia in uteroplacental and fetal Doppler studies

“…During labor the majority of women hyperventilate to some degree. Maternal hyperventilation (with concomitant hypocapnia) reduces uteroplacental blood flow13, 14–17, fetal cerebral blood flow18, and in the sheep model results in decreased fetal PaO 2 19. Women in labor with evidence of fetal distress or in whom a Cesarean section is being performed are often given supplemental oxygen.…”

“…On the maternal side, the uteroplacental circulation demonstrated decreased resistance to flow and increased PSV, which would translate to increased net blood flow to the uterus under conditions of normocapnic hyperoxygenation. Given the known influence of hyperventilation without hyperoxygenation on uterine blood flow 13 , hypocapnia may mask a vasodilatory effect of oxygen on the uteroplacental circulation.…”

Chronic Maternal Hyperoxygenation and Effect on Cerebral and Placental Vasoregulation and Neurodevelopment in Fetuses with Left Heart Hypoplasia

“…Animal studies have similarly suggested no change in PLVR with AMH [39,40]. Tervilä et al [41,42], however, reported decreased uterine perfusion in healthy fetuses and those with various noncardiac diseases in response to AMH. Jouppila et al [43] similarly found a significant decrease in intervillous blood flow in healthy fetuses exposed to AMH.…”