Timing of umbilical cord clamping has been the subject of intense discussion and randomized, controlled trials in term and preterm infants.1 After birth, delayed cord clamping (DCC) (30-180 seconds) is reported to increase neonatal blood volume. Immediate cord clamping (ICC) (< 30 seconds), which is more commonly practiced, is intended to facilitate resuscitation of the infant should it be needed.
Despite the debate, the ideal timing for cord clamping has not been established. Renewed interest in this question comes from the potential impact that DCC may have on cord blood banking and the concentration of stem cells returned to the infant versus cryopreserved for potential later use.
Benefits of delayed cord clamping
Many benefits and few disadvantages are associated with DCC especially in preterm infants:
- Benefits of Delayed Clamping to Preter m Infants
- Higher hemoglobin and hematocrit in the early neonatal period
- Higher systemic blood pressure between 4-24 hours of age
- Increased blood volume and reduced need for transfusions
- Reduced need for inotropic medications
- Increased urine output in first 24 hours
- Reduced incidence of intraventricular hemorrhage
- Improved myocardial function
- Improved cerebral oxygenation
- Transfer of autologous stem cells
Potential adverse effects
- Increased peak bilirubin values during the first week in preterm infants
- Increased need for phototherapy in both preterm and term infants
When it may be needed
DCC appears to be indicated in preterm infants as well as in births in underdeveloped countries where iron-deficiency anemia is commonplace. The American College of Obstetricians and Gynecologists specifically advises that cord clamping time should not be influenced by the need or desire for umbilical cord blood banking.
Benefits of more stem cells
It has been suggested that placental transfer of blood at delivery is mankind’s first natural stem cell transplant. It is believed that stem cells flowing to the infant function in the normal development of organ systems and may have long-term benefits against age-related diseases.No studies have been reported to directly test this hypothesis. Surprisingly, the number of circulating hematopoietic progenitor cells was higher when measured in the peripheral blood of infants following immediate versus delayed cord clamping, although the differences were not statistically significant. Clearly, the long-term consequence of timing of cord clamping on development is an intriguing question that deserves further exploration.
Some circumstances will clearly dictate when banking the cord blood stem cells for future therapeutic needs (e.g., family history of malignant, genetic or immunological disorders)is preferable to infusing additional red blood cells to the infant at birth (e.g., for suspected iron-deficient anemia). However, in most cases, neither of these criteria will apply yet the family may be conflicted on how to proceed. A possible compromise may be to delay clamping for sufficient time to allow a transient infusion of blood to the infant (30-60 seconds) without significantly compromising the volume of cord blood obtained for banking. This decision should be determined between the patient and her physician.