Abstract
The effect of maternal hyperoxia and hypoxia on Po2 Pco2, and pH in maternal arterial blood and in amniotic fluid was studied in 8 pregnant women in the second trimester. Hyperoxia with about 100% O2 gave an increase in maternal Pao2, to about 500–600 mmHg followed by a significant increase in amniotic fluid Po2. Pronounced hypoxia (10% O2) reduced maternal Pao2 to about 40 mmHg and caused a significant decrease in amniotic fluid Po2. Minor changes in Pco2, and pH of maternal arterial blood and amniotic fluid were seen during hyperoxia and hypoxia.