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TOPLINE:

Umbilical cord pH levels < 7.2 may increase the risk for adverse neonatal outcomes, a Danish national cohort study shows. Severe acidosis has typically been thought to occur < 7.0. Reconsideration of the threshold for more intensive observation may be warranted, according to the study authors.

METHODOLOGY:

• Researchers conducted a population-based cohort study that included 340,431 liveborn, singleton, full-term infants without malformations born in Denmark between 2012 and 2018.
• They categorized pH levels in the umbilical cord into four groups: < 7.00, 7.00-7.09, 7.10-7.19, and 7.20-7.50 (reference group).
• The primary outcome was a composite of severe adverse neonatal outcomes, including neonatal death, therapeutic hypothermia, mechanical ventilation, treatment with inhaled nitric oxide, or seizures.
• The researchers used modified Poisson regression models to estimate the difference in adverse outcomes between the groups.

TAKEAWAY:

• An umbilical cord pH < 7.00 was associated with an increased risk for severe adverse neonatal outcomes (9.8% vs 0.2% in the reference group).
• Severe adverse neonatal outcomes also were more likely for pH levels of 7.00-7.09 (0.8% vs 0.2%) and 7.10-7.19 (0.4% vs 0.2%; adjusted risk ratio, 1.60 [95% CI, 1.38-1.85]).
• Risk for neonatal death increased below a pH of 7.1, but not for 7.10-7.19, compared with the reference group, the researchers reported.

IN PRACTICE:

"Our findings indicate an association between [umbilical cord pH] levels and the risk of neonatal morbidity and mortality, even at levels not previously clearly related to adverse neonatal outcomes," the authors of the study wrote. "Knowing the risk of neonatal adverse outcomes at different levels of [umbilical cord pH] may lead to reconsidering the threshold for more intensive observation of infants to identify clinical conditions in which intervention is needed."

SOURCE:

Charlotte Brix Andersson, MD, with Aalborg University in Aalborg, Denmark, was the corresponding author of the study, which was published online on August 14 in JAMA Network Open.

LIMITATIONS:

The researchers were not able to distinguish between metabolic and respiratory acidosis. A pH < 7 is one of the criteria for treatment with therapeutic hypothermia, which influences the composite primary outcome results. The results may have limited generalizability to healthcare systems outside of Denmark.

DISCLOSURES:

The study was supported by the Elsass Foundation, the Dagmar Marshalls Foundation, and the Carsten Lenstrups Foundation. One author disclosed honoraria from Chiesi Farmaceutici as a member of the board for the Nordic Neonatal Meeting.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.