Delayed Cord Clamping Beyond 60 Seconds: What the Evidence Shows
Synthesising evidence from 10+ randomised trials and two landmark individual participant data meta-analyses on the optimal timing of umbilical cord clamping in term and preterm neonates — including the 2025 ACOG Clinical Practice Update.
This is an original evidence synthesis. See References for source studies.
One-Minute Takeaway
One-Minute Takeaway
- Strong evidence from the iCOMP individual participant data meta-analysis (>12,000 preterm infants across 48 RCTs) supports delayed cord clamping beyond 60 seconds as a strategy that reduces neonatal death before discharge, with the 2025 ACOG update now formally recommending a minimum 60-second deferral for preterm neonates.
- In term neonates, deferring cord clamping for at least 60–180 seconds consistently improves haemoglobin at birth, reduces iron deficiency at 3–6 months, and may benefit neurodevelopment, though it is associated with a modest increase in phototherapy-treated jaundice.
- Network meta-analysis data suggest a dose–response relationship in preterm infants, with the longest deferral (≥120 seconds) showing the greatest mortality reduction (OR 0.31), though this finding is based on small trial numbers with variable adherence.
- Key knowledge gaps remain regarding optimal timing beyond 120 seconds, applicability in non-vigorous neonates, safety of cord milking in infants below 28 weeks’ gestation, and long-term neurodevelopmental outcomes of extended deferral in very preterm populations.
Why Delayed Cord Clamping Timing Matters
The transition from fetal to neonatal circulation represents one of the most critical physiological events in human life. At the centre of this transition lies the umbilical cord — a conduit that, if left intact for even 60 additional seconds, can transfer roughly 80–100 mL of blood from the placenta to the newborn. This volume represents up to one-third of a term neonate’s total blood supply and carries with it haemoglobin, iron stores, stem cells, and immunoglobulins that support adaptation to extrauterine life.
For preterm infants — who account for approximately 15 million births worldwide annually — the implications are even more pronounced. The placenta holds roughly 50% of the circulating blood volume in very early preterm neonates, meaning that early clamping may deprive these vulnerable infants of a substantial proportion of their total blood supply. The publication of two companion individual participant data meta-analyses in The Lancet in 2023, combined with the 2025 ACOG Clinical Practice Update, has fundamentally shifted guideline recommendations from a general 30–60 second window toward a minimum of 60 seconds for preterm infants.
What Evidence Was Reviewed
This synthesis draws on two landmark individual participant data meta-analyses (iCOMP Collaborators, Lancet 2023), a Cochrane systematic review of cord clamping timing in term infants, a network meta-analysis comparing durations of deferral, a multicentre RCT of physiological-based cord clamping (ABC3), key trials examining neurodevelopmental follow-up, and the 2025 ACOG Clinical Practice Update. Evidence is current through early 2026.
| Study | Design | n | Population | Key Finding | Quality |
|---|---|---|---|---|---|
| iCOMP Pairwise MA (Seidler et al. 2023) | IPD meta-analysis of 48 RCTs | 6,834 | Preterm <37 wks | Deferred CC reduced death before discharge vs. immediate CC (OR 0.68, 95% CI 0.51–0.91) | High |
| iCOMP Network MA (Seidler et al. 2023) | IPD network meta-analysis of 47 RCTs | 5,627 | Preterm <37 wks | Long deferral ≥120 s showed largest mortality reduction (OR 0.31, 95% CI 0.11–0.80) | High |
| Cochrane Review (McDonald et al. 2013) | SR of 15 RCTs | 3,911 | Term neonates | Late CC doubled iron stores at 3–6 mo (RR 2.65 for deficiency with early CC); small jaundice increase | Moderate |
| Andersson et al. 2011 | RCT | 400 | Full-term, Sweden | DCC ≥180 s improved ferritin at 4 months without increased adverse effects | High |
| Andersson et al. 2015 | RCT follow-up | 263 | Term, age 4 years | DCC associated with improved fine-motor and social development, especially in boys | Moderate |
| Rana et al. 2019 / Kc et al. 2017 | RCT | 540 | Term, Nepal | DCC ≥180 s reduced risk of impaired neurodevelopment at 12 mo (RR 0.43); reduced anaemia at 8–12 mo | Moderate |
| Berg et al. 2021 | RCT follow-up | 350 | Term, Nepal, age 3 yrs | No significant difference in ASQ at 3 years (high attrition, 23% protocol deviation) | Low |
| Chaudhary et al. 2023 | 3-arm RCT | 204 | Late preterm/term, India | DCC 120 s increased haematocrit and polycythaemia vs. 30–60 s; no ferritin difference at 3 months | Moderate |
| ABC3 Trial (Knol et al. 2025) | Multicentre RCT | 669 | Preterm <30 wks, Netherlands | Physiological-based CC did not improve intact survival vs. time-based 30–60 s deferral | High |
| ACOG Clinical Practice Update 2025 | Guideline | NR | Preterm <37 wks | Recommends ≥60 s deferral; cord milking alternative for 28–36 wks; caution for ≥120 s routinely | Guideline |
Key Findings on Delayed Cord Clamping
Mortality Benefit in Preterm Neonates
The most consequential finding of the iCOMP collaboration is the mortality reduction associated with deferred cord clamping in preterm infants. Across 48 RCTs including 6,834 preterm neonates, deferring cord clamping for at least 30 seconds reduced the odds of death before hospital discharge by 32% compared with immediate clamping (OR 0.68, 95% CI 0.51–0.91). This effect was consistent across multiple subgroups, including gestational age at birth, mode of delivery, and whether the infant was a singleton or multiple.
The companion network meta-analysis revealed a dose–response pattern: longer deferral was associated with progressively greater mortality reduction. Infants receiving the longest deferral of at least 120 seconds had 69% lower odds of death (OR 0.31, 95% CI 0.11–0.80) compared with immediately clamped neonates. A post hoc ILCOR analysis focusing specifically on a 60-second or greater threshold found a 37% reduction in neonatal death (OR 0.63, 95% CI 0.44–0.88), which formed the basis of the 2025 ACOG recommendation. These data represent high-certainty evidence for the preterm mortality benefit.
Haematological Outcomes and Iron Status
Both term and preterm populations show consistent haematological benefits from delayed cord clamping. In the Cochrane review of 15 term infant trials, neonatal haemoglobin was approximately 1.5 g/dL higher at 24–48 hours with late versus early clamping. Although this difference did not persist beyond six months, the iron stores benefit was more durable: infants who underwent early clamping were over 2.5 times as likely to be iron deficient at three to six months of age (RR 2.65, 95% CI 1.04–6.73).
Among preterm neonates, the iCOMP analysis showed that deferred clamping of any duration reduced the need for blood transfusion in those born before 32 weeks by 41% (OR 0.59, 95% CI 0.47–0.73). The three-arm RCT by Chaudhary and colleagues, comparing 30-, 60-, and 120-second clamping in late preterm and term neonates, found that the 120-second group had approximately 2% higher mean haematocrit and higher polycythaemia rates, though serum ferritin at three months did not significantly differ across groups.
Neurodevelopmental Outcomes
The neurodevelopmental evidence spans several RCTs with follow-up from 12 months to 4 years. In a Swedish trial of 400 term infants, those randomised to delayed clamping (at least 180 seconds) demonstrated better fine-motor and social domain scores on standardised assessments at age four, with the strongest effects observed in boys. A parallel trial conducted in Nepal, where baseline anaemia prevalence is high, found substantially fewer infants in the delayed group meeting criteria for at-risk development at one year (RR 0.43, 95% CI 0.26–0.71).
However, these benefits may not persist uniformly. Follow-up of the Nepal cohort at three years found no statistically significant difference in developmental scores between early and delayed clamping groups, though significant attrition (approximately 35%) and protocol deviation (23%) limit the interpretability of this null finding. The observation that early iron deficiency may produce neurodevelopmental effects that become more apparent at later ages warrants further long-term follow-up of these cohorts.
Very preterm infants represent the population with the greatest potential benefit and risk from cord management strategies. The iCOMP analysis demonstrated that the mortality benefit of deferred clamping was consistent across gestational age subgroups, including the most premature neonates. However, adherence to deferred clamping drops substantially at lower gestational ages — Canadian registry data show that only 25% of infants below 26 weeks received at least 60 seconds of deferral, compared with higher rates at later gestational ages.
A key safety concern in this subgroup is the association between intact cord milking and severe intraventricular haemorrhage. An ILCOR analysis found that among preterm infants below 32 weeks, cord milking was associated with more than double the odds of severe IVH (OR 2.20, 95% CI 1.13–4.31), with one major trial halted early in the subgroup below 28 weeks due to excess haemorrhage. Current ACOG and ILCOR guidance therefore restricts the cord milking alternative to infants born at 28 weeks or later.
In term neonates, the evidence base is primarily shaped by the Cochrane review and several RCTs examining iron and neurodevelopment. The Cochrane analysis found no increased risk of postpartum haemorrhage with delayed clamping across five trials involving 2,236 women. Birth weight was approximately 101 grams higher with late clamping (95% CI 45–157 g). The small increase in phototherapy-treated jaundice (RR 0.62 for early clamping, 95% CI 0.41–0.96) remains a frequently cited concern, though this effect was largely driven by a single unpublished trial and was not replicated in later independent studies.
Caesarean delivery presents particular implementation challenges. Canadian registry data show that caesarean birth was associated with significantly lower odds of achieving deferred clamping (adjusted OR 0.39, 95% CI 0.33–0.47). This is likely multifactorial, reflecting time pressure in the operating theatre, concerns about maternal haemostasis, and logistical constraints around neonatal care at the operative field. Nonetheless, major trials have successfully implemented 60-second deferral during caesarean delivery without adverse maternal outcomes.
The ABC3 trial addressed whether clamping based on the infant’s physiological stability (heart rate above 100 bpm and SpO₂ above 85%) would outperform a fixed 30–60 second deferral in very preterm infants below 30 weeks. This high-quality multicentre Dutch trial randomised 669 infants and found no improvement in the composite primary outcome of survival without major cerebral injury or necrotising enterocolitis. Mortality rates were similar between groups.
This is a significant finding because it suggests that extending deferral beyond 60 seconds through a physiology-guided approach may not confer additional clinical benefit in the very preterm population, at least when the comparator is already a moderate deferral of 30–60 seconds rather than immediate clamping. The trial does not rule out benefit of longer fixed-time deferral (e.g. 120+ seconds), since the physiological-based group’s actual clamping times varied considerably. Importantly, no adverse maternal outcomes were identified with the physiological approach.
In LMICs, where maternal anaemia prevalence is high and neonatal iron deficiency is endemic, delayed cord clamping carries particular importance. The three-arm Indian RCT concluded that 30–60 seconds of deferral may represent a practical optimum for busy LMIC delivery settings — achieving meaningful haematological benefits without the increased polycythaemia rates seen at 120 seconds. The Nepal RCT demonstrated the most robust neurodevelopmental benefits at 12 months in a population with high baseline anaemia (72–78% among children 6–17 months).
Implementation remains a challenge: achieving consistent deferral requires delivery room protocols, timer systems, and multidisciplinary coordination. Quality improvement initiatives have shown that structured programmes can increase DCC compliance from under 15% to over 70%, suggesting that the primary barriers are organisational rather than clinical.
Quality & Consistency of Evidence
What the Evidence Does Not Show
No adequately powered trial has directly compared 60-second versus 120-second versus 180-second deferral as a primary comparison in preterm infants below 28 weeks’ gestation. The dose–response signal from the network meta-analysis relies on indirect comparisons and very small trial numbers at the longest deferral times.
For non-vigorous neonates — those who require immediate resuscitation at birth — the evidence is particularly sparse. Current guidelines exclude this population from routine deferral recommendations, yet these infants may physiologically benefit most from maintained placental circulation. The 2025 ILCOR systematic review on cord management in non-vigorous term infants represents an initial attempt to address this gap, but available data remain insufficient to support firm recommendations.
Long-term neurodevelopmental follow-up beyond 4 years is unavailable from any cord clamping trial. The effects of early iron status on school-age cognitive function, executive function, and behavioural outcomes remain uncharacterised. Additionally, the impact of deferred clamping on stem cell transfusion and long-term immune function has been hypothesised but not systematically evaluated in clinical trials.
The optimal protocol for multiple gestations and pregnancies complicated by placenta praevia, abruption, or fetal growth restriction remains undefined, as these populations were excluded from most included trials.
Practical Implications
Based on the current evidence, several considerations emerge for obstetric and neonatal teams.
High-certainty evidence links deferral of at least 60 seconds with reduced mortality and transfusion requirements in preterm infants not requiring immediate resuscitation. The 2025 ACOG update formally establishes 60 seconds as the recommended minimum, updating the previous 30–60 second range.
Deferring clamping for at least 60 seconds in vigorous term neonates provides measurable haematological and iron storage advantages through the first 6 months of life. Clinicians should maintain jaundice surveillance capacity, as a modest increase in phototherapy requirements has been observed in some studies.
When deferred clamping is not feasible for infants born between 28 and 36 weeks, cord milking represents a reasonable alternative for improving haematological parameters. However, cord milking is contraindicated below 28 weeks due to the observed association with severe intraventricular haemorrhage.
Despite strong evidence, implementation lags substantially in practice — fewer than half of eligible preterm infants in well-resourced settings achieve 60 seconds of deferral. Structured quality improvement programmes, including standardised timer protocols and team training, have demonstrated effectiveness in increasing compliance.
Evidence Grade & Bottom Line
Overall Evidence Grade: Strong (Preterm Mortality) / Moderate (Term Iron and Haematological Outcomes)
For the primary question of whether deferred cord clamping of at least 60 seconds reduces preterm neonatal mortality, the evidence is high-certainty and derived from individual participant data meta-analysis of 48 RCTs involving over 6,800 preterm infants. For term infant iron and haematological outcomes, evidence from 15 RCTs supports consistent benefit. The optimal duration beyond 60 seconds, particularly in very preterm infants, remains less certain.
- Deferred cord clamping of at least 60 seconds is now the evidence-based minimum standard for preterm infants not requiring immediate resuscitation, reducing mortality by approximately 37%.
- In term neonates, deferral of at least 60 seconds improves iron stores through the first six months and may support neurodevelopment, particularly in populations with high baseline anaemia.
- Longer deferral (≥120 seconds) shows the largest mortality reduction in preterm infants but is based on limited trial data — ACOG advises caution before routine adoption of durations beyond 60 seconds pending further evidence.
- Cord milking is a reasonable alternative when deferral is not feasible for neonates ≥28 weeks, but is contraindicated below 28 weeks due to the risk of severe intraventricular haemorrhage.
- Long-term neurodevelopmental follow-up and evidence for non-vigorous neonates, multiple gestations, and pregnancies with placental complications remain insufficient to guide practice in these specific clinical scenarios.
Article Information
For Educational Purposes Only. This is an original evidence synthesis informed by the studies listed below. It does not replace clinical judgement. Drug dosages should be verified against current prescribing information.
References
- Seidler AL, Aberoumand M, Hunter KE, et al. Deferred cord clamping, cord milking, and immediate cord clamping at preterm birth: a systematic review and individual participant data meta-analysis. Lancet. 2023;402(10418):2209-2222. DOI: 10.1016/S0140-6736(23)02468-6
- Seidler AL, Libesman S, Hunter KE, et al. Short, medium, and long deferral of umbilical cord clamping compared with umbilical cord milking and immediate clamping at preterm birth: a systematic review and network meta-analysis with individual participant data. Lancet. 2023;402(10418):2223-2234. DOI: 10.1016/S0140-6736(23)02469-8
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