Intrapartum Maternal Oxygen Supplementation—Friend or Foe?

Abstract

It has been estimated that 2 of 3 women in labor in the US receive oxygen supplementation for nonreassuring fetal heart rate patterns at some point during labor.¹ During the course of labor, maternal-fetal oxygen delivery is interrupted by uterine contractions and ceases when the contractions exceed 40 mm Hg in intensity, a level typically exceeded many times before delivery. This hypoxic stress results in the development of significant metabolic acidemia even under normal conditions, with the umbilical artery pH decreasing from a prelabor mean of approximately 7.38 to a mean pH of 7.25 at the time of delivery.² These changes occur despite numerous mechanisms that serve to mitigate the degree of tissue hypoxia and associated metabolic acidemia resulting from the process of labor, including a relatively high fetal hemoglobin level, enhanced oxygen-carrying capacity and tissue delivery by hemoglobin F, and high levels of fetal 2,3-disphosphoglycerate. Identify all potential conflicts of interest that might be relevant to your comment. Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. Err on the side of full disclosure. If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response. Not all submitted comments are published. Please see our commenting policy for details.