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. 2025 Oct 28;12(11):1462.
doi: 10.3390/children12111462.

Optimal Duration of Umbilical Cord Clamping with Ventilation in a Preterm Asphyxiated Ovine Model

Mausma Bawa  1 , Sylvia Gugino  1 , Justin Helman  1 , Nicole Bradley  1 , Lori Nielsen  1 , Arun Prasath  2 , Clariss Blanco  3 , Mary Divya Kasu  4 , Hamza Abbasi  1 , Munmun Rawat  1 , Praveen Chandrasekharan  1
Affiliations

Optimal Duration of Umbilical Cord Clamping with Ventilation in a Preterm Asphyxiated Ovine Model

Mausma Bawa et al. Children (Basel). .

Abstract

Background: There is inadequate evidence to support recommendations for the delayed clamping of umbilical cords in preterm neonates who are born non-vigorous. Objective: In a preterm bradycardic ovine model, our objective was to compare the effects of early cord clamping with ventilation (ECCV) and various time periods of delayed cord clamping with ventilation (DCCV) at 1 min (DCCV1), 2 min (DCCV2), 3 min (DCCV3), 4 min (DCCV4), and 5 min (DCCV5). The primary composite outcome was (i) incidence of achieving a combined heart rate (HR) ≥ 100 bpm and preductal saturation (SpO2) ≥80% by 5 min, and (ii) time to attain this outcome. Secondary outcomes were to evaluate gas exchange/hemodynamics. Methods: 32 preterm lambs of 126-128-day gestational age were randomized to one of six groups: ECCV (n = 5), DCCV1 (n = 6), DCCV2 (n = 5), DCCV3 (n = 6), DCCV4 (n = 6), and DCCV5 (n = 4). Asphyxia was induced by umbilical cord occlusion to attain a HR ≤ 90 beats per minute (bpm). Results: All lambs in DCCV5 achieved a primary composite outcome by 5 min. The time taken to achieve the primary composite outcome in DCCV5 was significantly lower (p = 0.02). Partial pressure of arterial carbon dioxide (PaCO2) was significantly lower (p = 0.0001) in DCCV5. Peak pulmonary blood flow (PBF) was significantly higher (p = 0.0001) in DCCV5 while peak carotid blood flow (CBF) was highest in the ECCV (p < 0.0001) compared to other groups. Conclusions: In a preterm ovine model of asphyxia, resuscitation with an intact umbilical cord for 5 min increased the incidence and reduced the time to achieve the primary composite outcome, while also improving gas exchange by enhancing pulmonary blood flow, compared to shorter durations of DCCV and ECCV. These findings suggest that DCCV for 5 min may offer physiological advantages in the resuscitation of non-vigorous preterm neonates, warranting further investigation in clinical settings.

Keywords: asphyxia; delayed cord clamping; neonatal resuscitation; neonatal transition; non vigorous preterm neonate; oxygenation; ventilation.

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Conflict of interest statement

The authors declare no conflicts of interest. The funders had no role in the design of the study, the collection, analysis, or interpretation of data, the writing of the manuscript, or the decision to publish the results.

Figures

Figure 1
Figure 1
Design and Methodology.
Figure 2
Figure 2
Sample size estimation was performed using one-way ANOVA in SAS 9.4. Single contrast coefficients were applied for ANOVA post hoc analysis, assuming an estimated group mean difference of 3 min and a standard deviation of 2 min. The x-axis shows the power and the y-axis the sample size. The advancing line graph shows an upward curve with 32 lambs showing a power of ~0.96.
Figure 3
Figure 3
Preductal Saturations. The graph here shows the time in minutes during resuscitation along the X axis and the preductal saturations on the Y axis. *: DCCV5 had significantly higher preductal saturations compared to DCCV1 (p = 0.001), DCCV3 and ECCV (p = 0.01). The black line shows the DCCV5 group attained preductal saturation of 80% by 5 min.
Figure 4
Figure 4
Supplemental oxygen use during the first ten minutes of resuscitation.
Figure 5
Figure 5
Partial pressure of oxygen in arterial blood. The graph here shows the time in minutes during resuscitation along the X axis and the arterial oxygen (PaO2) on the Y axis. There was no statistical difference between the partial pressure of oxygen in arterial blood.
Figure 6
Figure 6
Partial pressure of carbon dioxide in arterial blood. The graph here shows the time in minutes during resuscitation along the X axis and the arterial carbon dioxide (PaCO2) on the Y axis. Arterial carbon dioxide was significantly lower (p = 0.0001) in DCCV5 compared to other groups.
Figure 7
Figure 7
Pulmonary blood flow. The graph here shows the time in minutes during resuscitation along the X axis and the pulmonary blood flow (mL/kg/min) on the Y axis. The peak pulmonary blood flow (PBF) was significantly higher (p < 0.0001) in DCCV4 and DCCV5 compared to ECCV & DCCV1.
Figure 8
Figure 8
Carotid blood flow. The graph here shows the time in minutes during resuscitation along the X axis and the carotid blood flow (mL/kg/min) on the Y axis. ECCV had a significantly higher carotid blood flow compared to other groups (* p < 0.0001).
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