Brief Maternal Oxygen Inhalation in Third Trimester may Alter Fetal Hemodynamics, suggest study
A new study published in the BMC European Journal of Medical Research showed that brief maternal oxygen inhalation in third trimester leads to higher pulsatility index for the pulmonary artery (PPI) and lower cerebroplacental ratio (CPR). These changes suggest a potential impact on fetal circulation, warranting further investigation into its implications.
Newborns have not been demonstrated to benefit much from the maternal oxygen intake during birth. Its effect on fetal hemodynamics in the latter stages of pregnancy is yet unknown, though. Wu XQ and colleagues did this study to look into the relationship between fetal hemodynamic alterations and the maternal late-trimester oxygen inhalation. In particular, they analyzed if there are any possible advantages or disadvantages for the fetus from this approach and examined the short-term effects of maternal oxygen supplementation on fetal Doppler measurements.
Between January 2022 and December 2022, singleton pregnancies that had a prenatal ultrasound examination after 32[+0] weeks were the source of this retrospective data. The participants were divided into groups who inhaled oxygen and those that did not. Despite the lack of a therapeutic basis, oxygen inhalation was given at the mother's request, mostly because of worries about hypoxia from extended mask usage during the COVID-19 epidemic.
The pregnant women in the oxygen inhalation group were given 3 L/min of oxygen via nasal cannula for 30 minutes, and then they proceeded to the ultrasound department for a sonographic evaluation within an hour. Before analysis, the CPR and PPI were predetermined as the main outcomes. The Doppler index, placental pulsatility index (PPI), and cerebroplacental ratio (CPR) were computed for every woman. Additionally, fetal heart function was evaluated in M-mode or pulsed Doppler. In comparison to the non-oxygen inhalation group, the exposed maternal oxygen inhalation group showed lower birth weight, lower CPR, and greater PPI as the primary result.
The final analysis comprised a total of 104 singleton pregnancies (oxygen inhalation group: n = 48). The resistance indices of the middle cerebral arteries, ductus venosus, descending aorta, umbilical vein, uterine arteries, and umbilical arteries did not change significantly. Variations were seen in the oxygen inhalation group, though.
Significant differences were seen between the groups for indices that have a higher sensitivity for predicting negative outcomes: PPI was higher in the oxygen inhalation group than in the non-oxygen inhalation group, and CPR was similarly lower in the oxygen inhalation group. Furthermore, the group that inhaled oxygen had a considerably lower birth weight than the group that did not. Overall, a short oxygen intake by the mother during the third trimester was linked to notable alterations in the fetal hemodynamics, including a decrease in CPR and an increase in PPI.
Source:
Wu, X.-Q., Yang, X.-F., Ye, L., Zhang, X.-B., Hong, Y.-Q., & Chiu, W.-H. (2025). Maternal oxygen inhalation affects the fetal hemodynamic in low-risk with uncomplicated late pregnancy. European Journal of Medical Research, 30(1), 222. https://doi.org/10.1186/s40001-025-02456-z
