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Am J Perinatol 2024; 41(07): 853-858
DOI: 10.1055/a-1787-7408
Original Article

Umbilical Artery Cord Gas Abnormalities in the Presence of a Nuchal Cord in Term Singleton Pregnancies: A Cohort Study

Leilah Deborah Zahedi-Spung 
1   Regional Obstetrical Consultants, University of Tennessee-Chattanooga, Department of Obstetricsand Gynecology, Chattanooga, TN
,
Nandini Raghuraman
2   Division of Maternal Fetal Medicine, Washington University in St. Louis, St. Louis, Missouri
,
Ebony B. Carter
2   Division of Maternal Fetal Medicine, Washington University in St. Louis, St. Louis, Missouri
,
Alison G. Cahill
3   Dell Medical School, University of Texas at Austin, Austin, Texas
,
Joshua I. Rosenbloom 
2   Division of Maternal Fetal Medicine, Washington University in St. Louis, St. Louis, Missouri
4   Hadassah University Medical Center, Jerusalem, Israel
› Author Affiliations Funding The original prospective study Dr. Cahill was supported by the Eunice Kennedy Shrive National Institute of Child Health and Human Development (R01: HD 06161619-01A1).
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Abstract

Objective The clinical significance of nuchal cord (NC) at the time of delivery is unclear. Studies have found that NC is associated with lower umbilical artery (UA) pH. Since fetal hypercarbia precedes respiratory acidosis, we hypothesize UA pCO2 is elevated in neonates with NC at the time of delivery.

Study design This is a secondary analysis of a prospective cohort study of women with full-term singleton pregnancies admitted in labor or for induction of labor at an institution with a universal umbilical cord gas policy. We compared patients with NC at the time of delivery to those without NC. Women were excluded if they did not have validated UA gases, had a major fetal anomaly, or had an intrauterine fetal demise. The primary outcome of the study was UA pCO2. Secondary outcomes were other components of UA gas and neonatal morbidity composite. Baseline characteristics were compared utilizing chi-square or Fisher's exact test or the Student's t-test. UA gas parameters were compared using the Kruskal–Wallis test. Multivariable logistic regression was utilized to adjust for confounders.

Results Of the 8,580 study participants, 7,608 had validated umbilical cord gases. The incidence of NC in the population was 24.15% (n = 1,837). UA pCO2 was higher in those with NC than without (58 mm Hg [53–64] vs. 55 mm Hg [50–60], p < 0.01). There was a greater odds of hypercarbia in the NC group (pCO2 > 65 mmHg; adjusted odds ratio [aOR]: 1.97, 95% confidence interval [CI]: 1.72–2.25, p < 0.01). Additionally, the NC group was more likely to be mildly acidemic (pH < 7.2, aOR: 1.74, 95% CI: 1.51–2.01, p < 0.01). There was no difference in composite neonatal morbidity between the groups.

Conclusion NC is associated with an increased risk of hypercarbia and acidemia. However, this is not associated with increased risk of neonatal morbidity.

Key Points

  • Nuchal cord is associated with an increased risk of hypercarbia and mild acidemia.

  • Nuchal cord is not likely associated with neonatal morbidity.

  • Neonatal management should not be altered due to the presence of a nuchal cord at delivery.

Keywords

acidemia - hypercarbia - neonatal morbidity - nuchal cord

Note

The findings of this study were presented as a poster at the Annual Pregnancy Meeting that was held virtually due to the COVID-19 pandemic in January 2021.




Publication History

Received: 27 June 2021

Accepted: 17 February 2022

Accepted Manuscript online:
03 March 2022

Article published online:
27 May 2022

© 2022. Thieme. All rights reserved.

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