Delayed cord clamping in neonates: A global evidence-based review of physiology, outcomes, and clinical integration in term and preterm births

Literature screening and selection process

The initial search yielded a total of 1,124 articles from PubMed, Cochrane Library, Scopus, and Google Scholar. An additional 37 documents were identified through manual bibliography screening and targeted guideline repositories from WHO, ACOG, RCOG, and NICE. After the removal of duplicates, 978 unique articles remained. These records underwent a two-phase screening process. In the first phase, titles and abstracts were evaluated to assess relevance to the core objectives of the review. A total of 642 studies were excluded at this stage, primarily for reasons including irrelevance to neonatal cord clamping, non-human models, or commentary-based content lacking primary data or rigorous synthesis. The second phase involved full-text assessment of 336 articles. During this stage, studies were excluded if they lacked comparative data on delayed versus ICC, provided insufficient outcome measures, or addressed cord clamping as a secondary intervention in broader obstetric care models. A total of 101 studies were excluded at this point, leaving 235 full-text articles that met all inclusion criteria. Among these, 68 were RCTs, 84 were cohort or case-control studies, 14 were meta-analyses or systematic reviews, 32 were high-quality narrative or integrative reviews, and 37 were clinical guidelines or position statements from professional societies. Each observational study was graded using the NOS, and only those scoring ≥6 stars were included for further synthesis. Trials were appraised for design integrity, sample power, and outcome reliability. These final 235 sources form the evidence base of this review and are grouped thematically below to extract mechanistic understanding, clinical relevance, and systemic implications. The comprehensive screening and inclusion process undertaken to identify the final studies analyzed in this review is illustrated in Figure 2.

Physiological mechanisms of placental transfusion

DCC leverages a time-sensitive window during which blood continues to flow from the placenta to the newborn, facilitated by uterine contractions and the physiological differences in pressure between the placental and neonatal circulations. This process, known as placental transfusion, can transfer an estimated 20–40 mL/kg of additional blood volume within the first 1–3 min post-delivery. This volume includes not only erythrocytes but also iron, plasma proteins, immunoglobulins, and pluripotent stem cells essential for immune and tissue development.^[1-5,9-11]

The cessation of umbilical flow marks the physiological conclusion of fetoplacental circulation. ICC interrupts this process prematurely, leading to an abrupt reduction in preload and systemic blood volume. This can impair cardiac output, cause fluctuations in cerebral blood flow, and destabilize transitional physiology, particularly in preterm infants.^[6-8,12-14] Studies in lamb models and human neonates have demonstrated that clamping before lung aeration can lead to transient bradycardia and impaired oxygen delivery.^[8,13]

Delayed clamping facilitates smooth hemodynamic transition by allowing lung inflation before severing placental circulation, ensuring continuity of venous return to the heart and gradual autonomic adaptation. In addition, the retained blood improves hemoglobin levels and increases neonatal iron stores – crucial for neurodevelopment and anemia prevention in infancy.^[2,9,10]

Placental transfusion also serves a critical immunological role. The delayed transfer of maternal immunoglobulins and hematopoietic stem cells through DCC is thought to contribute to enhanced immune priming and reduced susceptibility to neonatal infections.^[5,15] These biologic advantages provide a compelling rationale for the broad implementation of delayed clamping as a physiological norm rather than an elective procedure. Key physiologic domains influenced by DCC are summarized in Table 3, which compares term and preterm infants.

Clinical outcomes in term neonates

In term infants, DCC has consistently demonstrated superior hematologic and developmental outcomes without increasing maternal or neonatal risks. A large body of evidence has shown that infants who undergo delayed clamping exhibit higher hemoglobin concentrations at birth and improved ferritin levels at 4–6 months of age.^[1,2,9,21] These hematological benefits translate into a significant reduction in iron-deficiency anemia, which is a known risk factor for impaired cognitive and psychomotor development.^[14,22]

A key concern historically linked to DCC in terms of births has been the theoretical risk of hyperbilirubinemia. However, pooled data from RCTs show only a marginal increase in bilirubin levels, with no significant elevation in phototherapy rates.^[3,14,22] This finding supports the safety of DCC even in resource-limited settings where phototherapy access may be constrained.

From a developmental standpoint, studies with longitudinal follow-up have indicated potential improvements in fine motor and personal-social domains among children who received DCC, suggesting long-term neuroprotective benefits.^[11,21] While causality remains under investigation, the observed correlations are biologically plausible given the established role of iron in myelination and synaptic development.

Moreover, DCC has not been associated with increased postpartum hemorrhage or maternal morbidity, alleviating early concerns that prolonging the third stage of labor could compromise maternal outcomes.^[3,17,24] Thus, in term neonates, the cumulative evidence strongly supports DCC as a low-cost, high-benefit intervention that improves early-life health trajectories.

Clinical outcomes in preterm neonates

In preterm populations, the evidence supporting DCC is even more compelling and urgent. Preterm neonates, particularly those born before 32 weeks, experience heightened risks for intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), sepsis, and death – conditions often linked to hemodynamic instability at birth. DCC in this population has been associated with reductions in all of these major morbidities, in addition to improved hematocrit levels and reduced need for red blood cell transfusions.^{[24-26,31,35,38]} Table 4 summarizes key clinical studies comparing delayed versus ICC in both term and preterm neonates, including primary outcomes, effect sizes, and methodological quality scores.

Mechanistically, allowing continued placental flow stabilizes cardiovascular function during the critical transition phase, reduces fluctuations in cerebral perfusion pressure, and improves oxygen delivery.^{[16,25,34,41]} These physiologic benefits translate into clinically significant risk reduction for Grade III–IV IVH, especially when lung aeration precedes cord clamping.

A meta-analysis of 18 trials involving over 2,800 preterm infants found a 30% reduction in in-hospital mortality in the DCC group compared to ICC.^[28] These data have led to a growing consensus that DCC should be the default approach in the delivery of preterm neonates, except in cases where immediate intervention is unavoidable. To support this consensus, evidence across the literature has been systematically evaluated and synthesized in Table 2, highlighting the strength, key insights, and limitations of each study reviewed. Moreover, the distinct physiologic advantages of DCC in preterm neonates are visualized in Figure 1, contrasting transitional circulation dynamics under immediate versus delayed clamping conditions.

Nevertheless, practical challenges persist. The perceived urgency to resuscitate, coupled with infrastructural limitations in some settings, continues to impede implementation. Strategies such as intact-cord resuscitation and mobile resuscitation trolleys have been developed to address this gap, though further research is needed to standardize these protocols across gestational age groups.

Perceived risks and misconceptions

Despite the mounting evidence supporting DCC, several perceived risks continue to hinder its universal acceptance. One of the most commonly cited concerns is the risk of neonatal hyperbilirubinemia and subsequent need for phototherapy. This concern is rooted in the assumption that the increased red cell mass transferred during placental transfusion would accelerate bilirubin production. However, meta-analyses and large RCTs have shown that while there is a modest increase in serum bilirubin levels, this rarely translates into clinically significant jaundice or higher phototherapy requirements.^[15,27,30] Importantly, these findings have remained consistent across settings with both high and low access to neonatal care resources.

A second concern relates to maternal outcomes, particularly postpartum hemorrhage and retained placenta. Early practices often prioritized uterine management over neonatal benefit, promoting ICC as a means to facilitate uterine contraction and placental delivery. However, multiple studies and guideline reviews have demonstrated no significant increase in maternal blood loss or duration of the third stage of labor when DCC is practiced correctly.^[6,13,18,44] These outcomes suggest that the maternal-fetal dyad need not be viewed in conflict, and that optimal neonatal outcomes can be achieved without compromising maternal safety.

In addition, logistical misconceptions – such as DCC being incompatible with resuscitation or surgical delivery – have further complicated adoption. The advent of PBCC, which aligns clamping with lung aeration rather than fixed time intervals, directly addresses this concern and supports safer transition, particularly in non-vigorous neonates.^[29,36,42] The resistance often stems not from scientific uncertainty, but from inadequate training, time pressures, and deeply entrenched clinical routines.

These persistent myths underscore the need for targeted educational interventions, updated protocols, and interprofessional collaboration to close the knowledge-practice gap and normalize DCC as a physiologically and ethically superior default practice.

Cord milking and physiologic-based clamping

As an adjunct or alternative to DCC, umbilical cord milking (UCM) has garnered interest, particularly in preterm and non-vigorous infants where immediate resuscitation is anticipated. UCM involves the manual expression of placental blood through the cord toward the infant, typically repeated three to 4 times before clamping. Theoretically, this technique offers a more rapid transfusion benefit while reducing the delay in initiating neonatal stabilization.

Clinical trials comparing UCM with DCC have reported mixed results. Some studies demonstrate comparable hematologic benefits, including improved hemoglobin and iron status.^[31,33,45] However, in extremely preterm neonates (<28 weeks of gestation), recent evidence has raised safety concerns, particularly regarding an increased risk of severe intraventricular hemorrhage.^[47,49] This has led several professional organizations, including ACOG and the American Academy of Pediatrics, to recommend caution or discourage UCM in the most vulnerable gestational cohorts.^[5,20]

PBCC represents a more nuanced and advanced approach to transitional care. Unlike time-based DCC, PBCC focuses on maintaining placental circulation until the onset of spontaneous or assisted respiration, thereby supporting cardiovascular stability before hemodynamic separation.^[28,50,51] This model is particularly advantageous in preterm neonates, where left ventricular preload and cerebral perfusion are sensitive to the timing of cord occlusion.

Early pilot trials of PBCC, especially those incorporating intact-cord resuscitation protocols, have demonstrated feasibility and improved hemodynamic markers.^[52-54] However, widespread implementation remains technically complex and dependent on delivery room infrastructure, interdisciplinary coordination, and resuscitation platform redesign. While UCM may offer practical value in certain emergent contexts, PBCC holds the greater promise for physiological harmony – if systems can adapt to support it. Key concepts related to comparative physiologic models, including UCM, ICC, and PBCC, are visually summarized in Figure 3, providing an outcome-oriented map of each intervention’s effect on both neonatal and maternal parameters.

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Figure 3:

Comparative evidence map: Cord clamping methods versus neonatal and maternal outcomes. This matrix visually compares five cord management techniques – immediate cord clamping (ICC), delayed cord clamping (DCC) (30s, 60s, >120s), and umbilical cord milking (UCM) – against major outcome domains: hematologic, neurodevelopmental, cardiopulmonary, maternal, and resuscitation-related effects. Color-coded circles indicate direction and strength of evidence: (Green) Positive outcome, (Yellow) Neutral/mixed, (Red) Negative effect. Circle size reflects cumulative strength and quantity of supporting literature. Key insights show that DCC, especially beyond 60 s, is associated with improved neonatal hematologic parameters and neurodevelopment. UCM shows some benefits but with variable evidence. ICC consistently shows the least favorable outcomes. This evidence map offers a concise, visual guide for clinical and policy decision-making. DCC: Delayed cord clamping.

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Comparison of international guidelines

An analysis of international guidelines reveals strong convergence on the recommendation to delay cord clamping in both term and preterm neonates, although variation persists in timing, terminology, and implementation protocols. The WHO recommends DCC for at least 60 s in all newborns who do not require immediate resuscitation, emphasizing its value in improving iron stores and reducing anemia prevalence in low-resource settings.^[6] The ACOG supports a 30–60 s delay in vigorous term and preterm infants,^[12] acknowledging emerging evidence on neuroprotection and transfusion avoidance. The RCOG echoes this position,^[14] but emphasizes individualized decision-making based on maternal and fetal status, especially during cesarean deliveries. NICE guidelines advocate for at least a 1-min delay unless clamping is contraindicated by neonatal or maternal compromise.^[15]

Despite this general agreement, terminology such as “early,” “immediate,” and “delayed” remains inconsistently defined, leading to operational ambiguity at the point of care. Moreover, few guidelines offer detailed implementation frameworks tailored to resource-limited settings, emergency scenarios, or integration with resuscitation. This lack of operational granularity has contributed to the observed variability in practice, particularly in low- and middle-income countries where equipment and personnel may limit the feasibility of intact-cord management. Table 1 provides a comparative summary of major international guidelines across different contexts, highlighting similarities and divergences in timing , practice constraints, and strength of recommendation. The evolution of scientific evidence and international endorsement of DCC is illustrated in Figure 4, highlighting major milestones including Cochrane reviews, WHO and ACOG guidelines, and widespread global adoption through 2025.

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Figure 4:

Timeline of scientific evidence and global guidelines on delayed cord clamping (2000–2025). This figure presents the chronological evolution of delayed cord clamping (DCC) from early research to global guideline integration. Key milestones include pivotal RCTs, Cochrane reviews, and adoption by major health organizations: 2006–2012: Core evidence emerged, including landmark trials and systematic reviews. 2014–2015: World Health Organization and royal college of obstetricians and gynecologists endorsed DCC as standard care. 2017–2020: Meta-analyses and updates from NRP and American College of Obstetricians and Gynecologists (ACOG) strengthened clinical consensus. 2021–2025: Broad international uptake with NICE 2023, ACOG 2025 reaffirmation, and increased implementation studies.

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There is an urgent need for harmonized, algorithm-based guidelines that not only recommend DCC but also operationalize it with clear protocols, flexibility for context, and integrated training modules. The future of DCC practice will depend not only on the strength of the recommendation but also on the clarity and feasibility of its execution.

Implementation barriers across clinical settings

While the evidence supporting DCC is now well-established, its real-world implementation remains highly uneven, influenced by clinical, cultural, institutional, and infrastructural factors. In high-income countries, barriers often stem from entrenched routines, time pressure in operating theatres, and concerns about coordinating neonatal resuscitation with intact cords. Resistance can also arise from fragmentation between obstetric and neonatal teams, where misaligned priorities lead to premature cord clamping despite institutional policies endorsing DCC.

In resource-limited settings, the barriers are more structural. Limited access to staff training, lack of standardized delivery room protocols, and absence of mobile resuscitation platforms often prevent DCC from being practiced – even when guidelines are available. In some cases, fear of litigation or cultural beliefs about placental disposal may further complicate the application of delayed clamping practices.

Implementation science studies suggest that successful DCC integration requires a multifaceted strategy: embedding protocols into electronic medical records, using visual prompts in labor wards, conducting simulation-based training, and fostering interprofessional collaboration. Moreover, context-specific adaptations – such as low-cost resuscitation trolleys or simplified timing protocols – can dramatically improve uptake in low-resource environments. Table 5 outlines the most commonly cited clinical, cultural, and systemic barriers across settings based on the reviewed studies.^[22-30] Figure 5 visualizes the global variation in guideline adoption for DCC, revealing stark contrasts between nations with national policies, those with partial uptake, and those lacking formal guidance altogether.

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Figure 5:

Global implementation of delayed cord clamping guidelines: A Policy Heatmap (2025). This heatmap visualizes the global distribution of delayed cord clamping (DCC) policy adoption as of 2025. Countries are color-coded based on the extent of implementation: green for nations with formal national DCC policies (e.g., UK, Canada, and India), yellow for partial or institutional-level uptake, and red for those lacking formal guidelines or maintaining outdated protocols. The classification is grounded in the 2014 World Health Organization global guideline on DCC, supplemented by national publications and implementation case studies. This figure highlights geographical disparities and underscores the urgent need for universal adoption to improve neonatal outcomes worldwide.

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Importantly, DCC is a low-cost intervention with high-yield outcomes, making it one of the most equitable perinatal innovations of the past two decades. Ensuring that all newborns, regardless of geography or delivery setting, benefit from physiologic transition is not merely a matter of evidence translation – it is a matter of perinatal justice.

Reframing cord clamping as a physiological imperative

The findings of this review consolidate a compelling biological and clinical rationale for DCC as a non-optional, physiologic component of neonatal transition. Placental transfusion is not a passive process but a critical phase of circulatory and respiratory stabilization. Evidence from animal and human models confirms that premature clamping before lung aeration compromises left ventricular preload and disrupts cerebral perfusion dynamics, especially in preterm neonates. This mechanistic insight justifies the transition from time-based to physiology-based cord management.

In both term and preterm neonates, DCC has demonstrated consistent benefits. Term infants experience improved iron stores, higher hemoglobin levels, and a reduced risk of iron-deficiency anemia – benefits substantiated in randomized trials and longitudinal cohort studies. Contrary to outdated concerns, the increase in bilirubin is minor and not associated with a clinically significant rise in phototherapy use. For preterm infants, the case is more urgent and more dramatic: DCC is associated with reduced IVH, lower transfusion rates, and a 30% relative reduction in neonatal mortality. These findings confirm that DCC is not merely beneficial – it is protective, especially in the most vulnerable populations.

Addressing myths and recalibrating risk perception

Despite this evidence, misconceptions persist. The theoretical association between DCC and maternal hemorrhage has been repeatedly refuted in systematic analyses and large clinical trials.^[12,19-21] Meanwhile, fears about delaying neonatal resuscitation fail to account for emerging practices such as intact-cord ventilation and PBCC.^[22,23,25] These approaches not only preserve the benefits of placental transfusion but may actually enhance cardiovascular stability and oxygenation during resuscitative efforts.

Cord milking, once considered a viable alternative in emergent settings, is increasingly recognized as context-dependent. While studies show comparable hematologic benefits in moderate-to-late preterms,^[27,30,32] data from extremely preterm infants reveal a concerning increase in IVH rates, particularly when milking is applied before lung aeration. As a result, major professional societies have advised against cord milking in infants under 28 weeks gestation.^[31,35] The trajectory of evidence clearly favors the physiologic primacy of intact, naturally regulated placental transfusion.

Policy alignment versus clinical reality

A major discrepancy lies between the clarity of global guidelines and the inconsistency of clinical practice. WHO, ACOG, NICE, and RCOG all endorse DCC for at least 30– 60 s, and most recommend longer when feasible.^[1,2,4,6] Yet, in audits across high-, middle-, and low-income settings, actual adherence rates to DCC protocols remain below 60% in many centers.^[5,15,17] This gap is not due to lack of evidence, but to systems-level inertia, fragmented training, delivery room time constraints, and clinician hesitancy.

In low-resource environments, where neonatal anemia and preterm mortality are disproportionately high, the barriers are largely infrastructural. Absence of trained personnel, mobile resuscitation platforms, or clear institutional guidelines restricts implementation – even though the benefits of DCC are potentially greatest in these settings. This creates a paradox: the most impactful intervention for reducing morbidity and mortality in the most vulnerable populations is the least likely to be delivered consistently.^[7,8,29]

Clinical integration and systems adaptation

Overcoming this discrepancy requires a multi-tiered implementation model. At the clinical level, labor and delivery protocols must redefine cord clamping as a critical clinical decision, not a routine procedural step. Interdisciplinary delivery teams must be trained in intact-cord resuscitation techniques and taught to prioritize physiological stability over procedural expediency. Simulation-based education has shown effectiveness in shifting behaviors, particularly when combined with visual decision aids and EMR prompts.^[33,36-38]

Institutional policy must also evolve. Hospitals should embed DCC into obstetric care bundles, monitor compliance metrics, and allocate equipment – such as mobile trolleys – for delivery room resuscitation under an intact cord. Furthermore, integration into national quality improvement initiatives can support system-wide uptake, especially when tied to performance-based funding or accreditation requirements.

In high-income countries, the challenge is cultural and logistical. In low-income countries, the solution must be adapted to material realities but is equally urgent. Cost is not a barrier – DCC is a no-cost, high-impact intervention. What remains is a gap in leadership, design, and intentionality. As illustrated in Figure 6, a structured clinical algorithm incorporating gestational age, neonatal status, and delivery mode can streamline decision-making and support consistent application of DCC across clinical settings.

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Figure 6:

Clinical decision algorithm for umbilical cord management in Newborns. This algorithm guides clinicians through evidence-based cord management based on three primary factors: gestational age, neonatal status at birth, and mode of delivery. Beginning with gestational age (term vs. preterm), the flow distinguishes between vigorous and non-vigorous neonates, and further by delivery type (vaginal or cesarean). Final clinical actions include delayed cord clamping, umbilical cord milking, or immediate clamping for urgent resuscitation. Designed for frontline use, this tool promotes optimal transitional physiology while respecting individual clinical contexts. It integrates insights from the World Health Organization, American College of Obstetricians and Gynecologists, neonatal resuscitation program, and recent meta-analyses to support rapid and informed decision-making. DCC: Delayed cord clamping.

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Ethical and equity considerations

Beyond physiology and logistics, DCC is an ethical issue. The unequal distribution of this life-saving intervention raises questions of perinatal justice. Neonates born into systems with evidence-informed, coordinated care receive the benefits of DCC as standard. Those born into overstretched, under-resourced, or protocol-deficient systems are denied the same physiologic start to life. This inequity is not defensible. Moreover, in settings where clinical teams default to ICC in anticipation of potential resuscitation – often without attempting intact-cord interventions – we must question whether fear is overriding evidence, and whether risk aversion is inadvertently harming the most vulnerable.^[7,22,33]

The principles of beneficence and non-maleficence support universal DCC implementation. From an ethical standpoint, failing to offer DCC in the absence of clear contraindications now borders on indefensibility. Informed consent frameworks for delivery planning should begin to include cord management options, empowering families to understand the science and express preferences.^[13,30]

Research frontiers and call to action

While much is known, critical gaps remain. Future studies must focus on refining physiologic-based clamping protocols across gestational ages and delivery modes. High-quality trials are needed to determine optimal timing strategies in non-vigorous term infants, and to explore long-term neurodevelopmental effects of various DCC durations.^[24,43,47] Comparative implementation science should evaluate how different hospital systems integrate DCC, and which policies most effectively close practice gaps. More inclusive research from low-resource settings is also essential to ensure global generalizability.^[15,28,35]

Ultimately, DCC must be reframed not as a “recommendation” but as a standard of care. Institutions, clinicians, and policymakers must align to dismantle structural inertia, standardize practice, and ensure every neonate receives the physiologic advantage they deserve.

Key takeaways

• DCC supports neonatal cardiovascular stability, improves iron status, and reduces mortality – especially in preterm infants.

• Myths regarding jaundice and maternal hemorrhage are unsupported by contemporary evidence.

• Cord milking is no longer recommended in extremely preterm infants due to IVH risk.

• PBCC and intact-cord resuscitation represent the future of transitional care.

• Global guideline consensus exists, but real-world practice is fragmented and inequitable.

• DCC is an ethical imperative and a feasible, zero-cost intervention that should be universally implemented.

Implementation checklist for DCC

Strengths, limitations, and future directions

Limitations of this review

While comprehensive, this review does not follow formal systematic review protocols such as PRISMA registration or risk-of-bias scoring for RCTs. As such, potential selection bias in study inclusion cannot be entirely excluded. The search was limited to English-language sources, which may have resulted in the exclusion of regionally important evidence published in other languages. Furthermore, due to the narrative format, quantitative synthesis (e.g., meta-analysis) was not performed, which limits the ability to generate pooled estimates or effect sizes for specific outcomes.

Another limitation is the heterogeneity of definitions and clinical settings among the included studies. Variability in what constitutes “delayed” or “immediate” cord clamping across studies, and differences in timing, technique, and outcome measurement, complicate direct comparison. While this heterogeneity reflects real-world complexity, it also limits the ability to draw uniform recommendations in certain subpopulations, such as infants requiring advanced resuscitation or those born through emergent cesarean.

Future directions

Future research must address several critical gaps. First, there is a need for large-scale, multicenter trials that evaluate PBCC across gestational ages and delivery contexts, including operative and non-vigorous births. These studies should include long-term neurodevelopmental follow-up to assess cognitive, behavioral, and functional outcomes associated with varying cord management strategies.

Implementation science must also take center stage. Studies that evaluate how DCC protocols are adopted – or fail – in different systems, particularly in low-resource settings, are urgently needed. This includes comparative studies of training models, equipment use, policy integration, and interprofessional collaboration. In addition, ethically grounded research into parental preferences, shared decision-making, and cultural attitudes toward cord management will be essential for global uptake.

Finally, emerging technologies such as intact-cord monitoring, resuscitation platforms, and telehealth-supported delivery units could reshape how DCC is delivered and studied in the next decade. As science advances, policy must keep pace, ensuring that innovations in neonatal care do not widen global inequities, but rather close them.