Timing of umbilical cord clamping has been the subject of discussion and randomized, controlled trials
in pre-term and full term infants
. After birth, delayed cord clamping (DCC), which is clamping of the umbilical cord between 30 seconds and 180 seconds, is reported to increase neonatal blood volume. Immediate cord clamping (ICC), which is anything within 30 seconds of delivery and 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 firmly, but recommendations have been made. In January 2017, the American College of Obstetricians and Gynecologists (ACOG) recommended delaying the clamping of the umbilical cord for 30–60 seconds for all healthy infants
. This was an update to similar guidelines it established in 2012
. Those guidelines recommended delayed clamping in preterm and vigourous-term babies. The latter being defined as a baby who is breathing and has good muscle tone and a heart rate above 100 beats per minute.
Renewed interest in this question comes from the potential impact that DCC may have on banking of the baby's cord blood 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 and term infants:
- Improved transitional circulation
- Better establishment of red blood cell volume
- Decreased need for blood transfusion
- Lower incidence of brain hemorrhage and intestinal disease
- Increased hemoglobin levels at birth
- Improved iron stores for several months, which helps prevent iron deficiency during the first year of life
- Higher systemic blood pressure between four and 24 hours of age
- 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 is the need strongest
DCC appears to be indicated in preterm infants and births in underdeveloped countries where iron-deficiency anemia is commonplace. ACOG 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). In most cases, however, 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.
While any reduction in volume can have an affect on the number of stem cells, an advanced cord blood–processing method called PrepaCyte-CB
has been shown to be unaffected by volume. The PrepaCyte-CB method, even if the volume of the collection is diminished (lower than the average volume collected with immediate cord clamping), won’t negatively impact the effectiveness of the stem cell collection.
As with many of the other decisions regarding the child's birth, this decision should be made between the patient and her physician.