Related Experiment Video
Updated: May 22, 2026

The Perinatal Asphyxiated Lamb Model: A Model for Newborn Resuscitation
Published on: August 15, 2018
Maternal hyperventilation during labor revisited: its effects on fetal oxygenation
Takuji Tomimatsu1, Aiko Kakigano, Kazuya Mimura
1Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Yamadaoka, Suita, Osaka, Japan. tomimatsu@gyne.med.osaka-u.ac.jp
To investigate the relationship between maternal hyperventilation and fetal blood gas values and to estimate its possible association with fetal oxygenation, maternal transcutaneous partial pressure of carbon dioxide (tcP(CO2)) values were analyzed in association with umbilical venous P(CO2) (UVP(CO2)), umbilical venous partial pressure of oxygen (UVP(O2)), and umbilical venous oxyhemoglobin saturation (UVHbo (2)) values. Pregnant women without labor (30.7 ± 3.7 mm Hg, n = 20) showed significantly lower tcP(CO2) values compared with nonpregnant women (37.4 ± 4.0 mm Hg, n = 10). Pregnant women in the second stage of labor showed even lower tcP(CO2) values compared with pregnant women during the first stage of labor (20.8 ± 5.9 mm Hg vs 28.4 ± 5.0 mm Hg, n = 26). Maternal tcP(CO2) values had significant positive correlations with UVP(CO2) (r = .78, P < .001), UVP(O2) (r = .62, P < .001), and UVHb(O2) values (r = .59, P < .001). Maternal hyperventilation had a close relationship with lower UVP(CO2), UVP(O2), and UVHbo(2) values, which might interfere with optimal fetal cerebral oxygenation.
To investigate the relationship between maternal hyperventilation and fetal blood gas values and to estimate its possible association with fetal oxygenation, maternal transcutaneous partial pressure of carbon dioxide (tcP(CO2)) values were analyzed in association with umbilical venous P(CO2) (UVP(CO2)), umbilical venous partial pressure of oxygen (UVP(O2)), and umbilical venous oxyhemoglobin saturation (UVHbo (2)) values. Pregnant women without labor (30.7 ± 3.7 mm Hg, n = 20) showed significantly lower tcP(CO2) values compared with nonpregnant women (37.4 ± 4.0 mm Hg, n = 10). Pregnant women in the second stage of labor showed even lower tcP(CO2) values compared with pregnant women during the first stage of labor (20.8 ± 5.9 mm Hg vs 28.4 ± 5.0 mm Hg, n = 26). Maternal tcP(CO2) values had significant positive correlations with UVP(CO2) (r = .78, P < .001), UVP(O2) (r = .62, P < .001), and UVHb(O2) values (r = .59, P < .001). Maternal hyperventilation had a close relationship with lower UVP(CO2), UVP(O2), and UVHbo(2) values, which might interfere with optimal fetal cerebral oxygenation.
Related Concept Videos
Hyperpnea and Hyperventilation
Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
Acute Respiratory Failure-II
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
Oxygen Transport in the Blood
Alterations in Respiration II
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes include...
Respiratory Assessment: Purpose and Indications
Objectives and Importance:
The primary goal of respiratory assessment is to evaluate patients at early risk of clinical deterioration. Since respiratory distress often precedes other signs of declining health, breathing patterns and sounds become a...

