Introduction: purpose of delayed cord clamping review
The International Liaison Committee on Resuscitation (ILCOR) has recommended delayed cord clamping (DCC) at birth for more than a decade, but it has not been universally implemented due to a lack of consensus.
Many variables impact placental transfusion and cardiopulmonary stability during the immediate transition, which are the two main goals of DCC. These include:
- Gestational changes in distribution of blood between fetus and placenta can slow equilibrium after birth in preterm infants
- Onset of ventilation strongly influences circulatory patterns, volume of placental transfusion; rarely documented in relationship to cord clamping
- Failure to breathe may shorten time-based approaches, like umbilical cord milking (UCM) in preterm infants
Evidence is growing around the important role of cord management for safe transition. Neonatology researchers from Children’s Hospital Colorado sought to explore the nuances informing management decisions and putting DCC into practice on a case-by-case basis. They examined recent literature on the benefit of DCC for term and preterm infants and the potential risks, including exaggerated hyperbilirubinemia and intraventricular hemorrhage (IVH).
Findings: summary of literature on benefits and risks of DCC
Benefits of delayed cord clamping for term and near-term infants
DCC improves hemoglobin/hematocrit among term infants and may promote improved neurodevelopment.
No known association with increased hyperbilirubinemia:
- Within five minutes of birth in term infants, DCC improved physiological stability, including improved heart rate and oxygen saturation (SpO2)
- No association of hyperbilirubinemia requiring phototherapy with DCC (2 min.) or UCM in healthy term infants
- In infants of diabetic mothers, DCC did not increase the need for phototherapy to treat jaundice
Potential neurodevelopmental benefit from the increased iron load from placental transfusion:
- Compared to early cord clamping (ECC), infants 2 to12 months old who received DCC had increased hemoglobin, ferritin and mean corpuscular volume
- Compared to ECC, term infants receiving DCC (5 min.) at 4 and 12 months old, had increased myelin content in areas of the brain known for motor function, visual and spatial skills, sensory processing
Umbilical cord milking
UCM is a popular approach to preterm infants because it can rapidly move them to receive respiratory support. It is associated with severe intraventricular hemorrhage (IVH) in extremely preterm infants due to the rapid increase in blood flow and fluctuations in cerebral blood flow:
- Very evident when comparing UCM to DCC
- May have been previously overlooked when comparing UCM to ECC, a potential risk factor for IVH
For extremely preterm infants, DCC as compared to UCM consistently shows improved mortality and a better safety profile related to severe IVH.
Physiologic-based cord clamping and intact cord resuscitation
Clamping after onset of respirations or delivery of respiratory support avoids reflex bradycardia, compensatory tachycardia and swings in blood pressure and flow.
Feasibility trials show physiologic-based cord clamping (PBCC) with clamping after breathing and respiratory stability and intact-cord resuscitation (ICR), where assisted ventilation is provided with cord intact, can facilitate smooth cardiopulmonary transition and placental transfusion. Other studies found:
- ICR improved ventilation and pulmonary blood flow in asphyxiated preterm lambs
- PBCC with clamping after ventilatory support can decrease time to clinical stability in preterm infants
- PBCC supported thermoregulation through continued perfusion with warm placental blood in a lamb model
- PBCC supports the triad of immediate delivery room necessity: ventilation, placental transfusion and thermoregulation.
- Compared to ECC, ICR showed decreased risk of death or adverse neurologic outcome in preterm infants at 2 years of life.
Special considerations: several populations may benefit from DCC
Infants of COVID-19 positive mothers
- Did not contribute to the spread of COVID-19 from mother to baby
- American Academy of Pediatrics policy statements support DCC as standard of care
- Obstetric colleagues should participate in planning for umbilical cord management, baby should be carefully monitored at delivery
- Similar outcomes between singletons and multiples less than 33 weeks gestation of mono/di/and tri chronicity receiving DCC
- DCC associated with decreased transfusions, length of stay in twins compared to twins who underwent ECC
Cardiopulmonary anomalies and extreme immaturity
- Other populations at risk for immediate respiratory insufficiency at birth may benefit from prolonged use of the placental circuit
- ICR may act as a biologic safety net to support safe transition in a growing list of clinical situations previously considered exclusions
Discussion and conclusion: DCC implementation challenges and future studies
Quality improvement strategies are useful in promoting implementation of DCC. The approach now incorporates evidence review, addresses concerns of obstetrical and pediatric clinicians, creates an agreed-upon management plan and monitors outcomes.
Umbilical cord management research has progressed to studying methods addressing individual needs of specific infant populations to optimize benefits. Future studies in umbilical cord management, mainly PBCC after ventilation, could expand benefits of ICR to non-vigorous infants.