465 - Association of Delayed Cord Clamping Duration with Time to Target Oxygen Saturation and Heart Rate in Preterm Infants

Publication Number: 1447.465

Athanasios Chamzas, University of Maryland School of Pharmacy, BALTIMORE, MD, United States; Nikki Brown, University of Maryland Medical Center, Upper Marlboro, MD, United States; Anna Macek, University of Maryland Galisano’s Children's Hospital, Reisterstown, MD, United States; Mathangi Gopalakrishnan, University of Maryland School of Pharmacy, Baltimore, MD, United States; Sripriya Sundararajan, University of Maryland School of Medicine, Baltimore, MD, United States

Background: Delayed cord clamping (DCC) facilitates placental transfusion and smoother cardiopulmonary transition in preterm neonates. However, the optimal DCC duration to achieve physiologic targets for heart rate (HR) ≥100 bpm and oxygen saturation (SpO₂) ≥90% remains uncertain. Defining these thresholds can help balance transfusion benefits with resuscitation concerns.

Objective: To evaluate the association between DCC duration and the time to reach HR ≥100 bpm and SpO₂ ≥90% during the first minutes after birth in spontaneously breathing preterm infants.

Design/Methods: Prospective observational study of infants 28-37 weeks of gestation born at the University of Maryland Medical Center (2021-2022). Continuous HR and SpO₂ data were collected with Masimo Rad-97 pulse oximetry during the first 15 minutes of life. Infants requiring positive pressure ventilation or with multiple major congenital anomalies were excluded. Time-to-SpO₂ ≥ 90% was compared across DCC categories (none, 1-30s, 31-59s, ≥60s) using Kaplan-Meier analysis. A Cox proportional hazards model was developed to evaluate the association between DCC duration and time to achieve SpO2 ≥90%, adjusting for gestational age, birthweight, sex, delivery mode, and antenatal steroids.

Results: Thirty-seven infants were included with a median GA of 35 weeks and mean birthweight of 2.2 kg. Oxygenation improved progressively with longer DCC: median time to reach SpO₂ ≥90 % was 487s (no DCC), 332s (1-30s), 316s (31-59s), and 295s (≥ 60s). The Cox model indicated that each additional second of DCC increased the likelihood of reaching SpO₂ ≥ 90% by about 1% (HR 1.01 [95% CI 0.99-1.03]). This translates to roughly an 80% higher overall rate of attaining oxygen saturation targets for infants with 60s of DCC compared with immediate clamping. Heart-rate patterns followed a similar trend: all infants reached HR ≥ 100 bpm within four minutes, with median times around 240s for those with 31-60s of DCC, confirming stable cardiovascular transition. Compared with infants who had < 60s of DCC, those with ≥60s DCC required fewer delivery-room resuscitations (19% vs 50-80%, p = 0.014) and had shorter NICU stays (median 4 [3-6] vs 9 [5-13] days). No differences were observed in early morbidities or evidence of hypothermia.

Conclusion(s): A one-minute delay in cord clamping was linked to faster attainment of oxygenation goals, stable heart-rate transition, and shorter hospitalization, without compromising safety in preterm infants. These findings support ≥60s of DCC as a physiologically sound and clinically feasible practice for preterm deliveries.



Kaplan Meier curve for SpO2 ≥ 90 by DCC duration category
Kaplan-Meier survival curves depicting cumulative probability of attaining oxygen saturation ≥ 90% during the first 15 minutes after birth, stratified by DCC duration. Longer DCC was associated with faster oxygenation, with the steepest early rise observed in infants receiving 60 s of DCC.

Association between DCC duration and time to achieve SpO₂ ≥ 90 %
Cox proportional-hazards model showing the adjusted hazard ratio for achieving SpO₂ ≥ 90% as a function of DCC duration. Each additional second of DCC increased the likelihood of reaching oxygenation targets by ~1% (HR 1.01 [95% CI 0.99-1.03]), supporting a dose-response relationship favoring longer DCC.