An increasing number of patients are inquiring about delayed cord clamping (DCC). This correlates with the recent recommendation by the World Health Organization (WHO) that “the cord should not be clamped earlier than is necessary.”1
Differences in opinion exist about the optimal timing of clamping the umbilical cord, which stems from weighing the benefits for the mother versus the neonate. Numerous randomized controlled trials (RCTs), Cochrane reviews and other research have not produced a consensus.
The American Congress of Obstetricians and Gynecologists (ACOG) endorses DCC in preterm infants stating that “evidence exists to support delayed umbilical cord clamping in preterm infants, when feasible.” However, regarding full-term infants, ACOG states that “evidence is insufficient to confirm or refute the potential for benefits from delayed umbilical cord clamping in term infants.”2
Timing of DCC
Many studies in both full and preterm infants vary on the appropriate timing for ICC versus DCC. Different studies use varying guidelines to determine the intervals, which define ICC and DCC of the umbilical cord.
For the full-term infant, ICC has been defined by various studies as clamping the cord immediately postpartum to up to 60 seconds later. DCC, on the other hand, is defined as clamping the cord from 30 seconds up to three minutes after delivery.3-5
Additionally, several studies seem to have used cessation of the cord pulse to define DCC.3,4 In the preterm infant, ICC is classified as cord clamping 5 to 15 seconds postpartum.4 Like in the full-term infant, DCC in the preterm neonate consists of clamping the cord 30 seconds up to 3 minutes after delivery.5 As seen throughout the literature, there is significant controversy about the proper definition of ICC and DCC in both full and preterm neonates.
Position of the Infant
According to ACOG, the neonate should be held at or below the level of the placenta after delivery.2
Some researchers, however, believe that the ideal position is for the infant to be placed on the mother for immediate skin-to-skin contact.3,6
Despite contrasting views about optimum position for the infant, most RCTs recommend that newborns be held at or below the level of the placenta to allow for easy blood flow and increased blood volume to the neonate.2
Benefits of DCC
Many positive effects on the neonate occur as a result of DCC, including an increase in placental transfusion, a 30% increase in neonatal blood volume, and a 60% increase of RBCs.4
The transfer of blood through the umbilical cord from the placenta to the newborn continues until the umbilical arteries constrict and cord pulsation ceases. However, the majority of blood transfer occurs in the first minute. DCC at 1 minute results in approximately 80 mL of blood volume transferred from the placenta on average and an additional 20 mL/kg for the next 2 minutes.5Another widespread benefit of DCC is the increase in iron levels in the infant. Iron deficiency is the leading cause of anemia, which can lead to serious consequences, such as cognitive impairment and central nervous system problems.4 By performing DCC, studies show an additional 40 mg/kg to 50 mg/kg of iron is transferred to the neonate.4 This, in turn, decreases the risk of iron deficiency anemia (IDA) in term infants (>37 weeks).7
In addition to an increase in iron, studies have shown that DCC also raises the Hgb and Hct levels at the time of birth.1,8 These effects were still obvious at 28 days, with higher levels of Hct appearing on the lab results of DCC infants.9 The neonates who experienced DCC had a 45% higher ferritin concentration and a decreased incidence in anemia for up to 4 to 6 months after birth.10 This validates the conclusion that a reduction in IDA is a long-term benefit of DCC. A reduction in IDA also decreases the risk of infection and developmental delays, making it important in every population.7Decreased rates of interventricular hemorrhage (IVH) and late onset sepsis (LOS), resulting from increased blood volume and hemoglobin concentration, have also been observed.7 There is a significant decrease in the risk of IVH and LOS in infants with DCC.11 The theory behind the decrease is the presence of high concentrations of hematopoietic progenitor cells in the cord blood. The hematopoietic progenitor cells result in an increase in blood volume. With an increase in blood volume comes an increase in progenitor cells in the circulation, which results in a decrease in immunosuppression and less infections.7
Similar benefits to those observed in the full-term neonate have been demonstrated in the preterm infant. In preterm infants in the DCC group, a decreased requirement for neonatal blood transfusions to treat anemia has been noted. The etiology for this decrease is also related to the increase in hematopoietic progenitor cells as observed with the full-term infants in the DCC group. Therefore, as a result of both the increase in blood volume and the decrease in immunosuppression, there is a decrease in IVH and LOS in the preterm infant.7 The higher incidence of IVH and LOS observed in the ICC group has been linked to developmental delay and lower motor scores 7 months post-delivery. When DCC was performed, a lower incidence of IVH and LOS was found, with a decreased incidence of neurodevelopmental delay.12
Preterm infants with ICC are at a higher risk of hypovolemia compared to full term infants. This is secondary to a higher blood volume in the placenta of preterm infants when compared to full-term infants. When DCC is performed, however, the increase of blood volume is especially beneficial in perfusion of the fetal lung tissue.12 DCC in the preterm infant can decrease the prevalence of respiratory distress, thereby reducing the need for respiratory support. DCC has also shown potentially beneficial hemodynamic changes, such as significantly higher superior vena cava (SVC) blood flow as well as greater right ventricle output and right ventricular stroke volume at 48 hours.13 The authors postulated that increased SVC blood flow may attenuate periventricular hemorrhage and periventricular leukomalacia.13
Three of the major concerns affecting the infants associated with DCC are the risk of hyperbilirubinemia, polycythemia and respiratory distress; however, significant research does not support substantial risk of these conditions to neonates receiving DCC.
Hyperbilirubinemia: It has been hypothesized that infants from the DCC group will have a higher incidence of hyperbilirubinemia due to increased iron stores that have been observed for up to 6 months after birth in infants with DCC.
Consequently, there are concerns they will require phototherapy for jaundice. A 2008 Cochrane review of five clinical trials assessing the effect of umbilical cord clamping on mothers and infants demonstrated a significant increase in the need for phototherapy to treat jaundiced infants with hyperbilirubinemia in the DCC group.2
Conversely, other reviews found no significant difference in mean serum bilirubin levels. There was no increased risk of jaundice within the first 24 hours, either. A lack of significant difference of jaundice between the two groups at 3 to 14 days post-delivery has also been reported.4
Polycythemia: Another proposed risk of DCC has been derived from the excess blood flow to the neonate, and suggests a major concern for the development of blood hyperviscosity.4 It has been postulated that DCC may result in an increased potential for fetal polycythemia.7
With DCC, infants may receive an additional 80 mL of blood within the first minute and up to 100 mL within the first 3 minutes. Neonatal polycythemia seems to occur more prevalently in pregnancies with risk factors such as intrauterine growth retardation and gestational diabetes mellitus, as well as living at high altitudes.2 A Cochrane meta-analysis found no significant difference in the laboratory work of the ICC versus DCC groups that would indicate that infants in the DCC group are at an increased risk for developing polycythemia.4
Respiratory distress: Delayed absorption of lung fluid due to an increase in blood volume from DCC may result in transient tachypnea. A Cochrane review found a similar number of infants in both the ICC and DCC group with respiratory distress being admitted to a neonatal intensive care unit.1
Many studies have proven the benefits of DCC for preterm infants and that DCC has no effect on APGAR scores nor does it increase the risk of respiratory distress syndrome. However, if the infant is in respiratory distress, DCC may delay resuscitation efforts; it is not recommended for non-vigorous infants who require resuscitation.7, 14
Concerns about DCC do not only surround the neonate, but also the mother. It has been suggested that DCC may lead to an increase in postpartum hemorrhage.
The rate of blood flow through the arteries and veins of the cord is approximately 600 mL/min. No statistical evidence proves that late cord clamping results in an increase in blood loss. There is no significant difference regarding greater than a 500 mL of blood loss between early and late cord clamping groups.
There was no significant difference between the two groups in mean maternal blood loss, maternal Hgb values 24 to 72 hours post-delivery, mothers requiring a blood transfusion, need for manual placental removal, or the necessity for administration of an uterotonic agent to decrease bleeding.4
The conclusions of much research show that standardized protocols for DCC are needed.
Guidelines about the ideal time of delay need to be set. Other unresolved issues include the logistics of DCC in cesarean sections, what should occur in infants with high risk for polycythemia, and the time for cord clamping in mothers at high-risk (HIV positive, hepatitis A/B/C positive, or with placenta previa).15
Perhaps if further research can demonstrate a clear advantage and establish consistent guidelines about DCC, clinicians would be more apt to implement this practice.
Bracha Sachs practices emergency medicine at New York Presbyterian Hospital/Columbia University Medical Center and neurosurgery at Mount Sinai Roosevelt Hospital. Danielle Daughtridge is a board certified physician assistant specializing in medical and cosmetic dermatology. She currently works at Schweiger Dermatology in Manhattan. Elizabeth Wallach is an emergency medicine physician assistant practicing in New York City at Lincoln Medical and Mental Health Center and NYP/Weill Cornell Medical Center. Jean Covino is a clinical professor at Pace University-Lenox Hill Hospital in New York City. NJ.
1. McDonald SJ, et al. Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes. Cochrane Database Syst Rev.. 2013;(7):CD004074.
2. Committee on Obstetric Practice. Committee opinion No.543: Timing of umbilical cord clamping after birth. Obstet Gynecol. 2012;120(6):1522-6. doi: 10.1097/01.AOG.0000423817.47165.48.
3. Andersson O, et al. Effects of delayed compared with early umbilical cord clamping on maternal postpartum hemorrhage and cord blood gas sampling: a randomized trial. Acta Obstet Gynecol Scand. 2013;92(5):567-74.
4. Eichenbaum-Pikser G, Zasloff J. Delayed clamping of the umbilical cord: A review with implications for practice. J Midwifery Women’s Health. 2009;54(4):321-26.
5. Raju TN. Timing of umbilical cord clamping after birth for optimizing placental transfusion. Curr Opin Pediatr. 2013;25(2):180-87.
6. Kaempf JW, et al. Delayed umbilical cord clamping in premature neonates. Obstet Gynecol. 2012;120:325-330.
7. Garofalo M, Abenhaim H. Early versus delayed cord clamping in term and preterm births: a review. J Obstet Gynaecol Can. 2012;34(6):525-31.
8. Jaleel R, et al. Timing of umbilical cord clamping and neonatal haematological status. J Pak Med Assoc. 2009;59(7):468-70.
9. Strauss RG, et al. A randomized clinical trial comparing immediate versus delayed clamping of the umbilical cord in preterm infants: short-term clinical and laboratory endpoints. Transfusion. 2008;48(4):658-665.
10. Rabe H, et al. Effect of timing of umbilical cord clamping and other strategies to influence placental transfusion at preterm birth on maternal and infant outcomes. Cochrane Database Syst Rev. 2012:8; CD003248.
11. Raju T, Singhal N. Optimal timing for clamping the umbilical cord after birth. Clin Perinatol. 2012;39(4):889-900.
12. Mercer JS, et al. Seven-month developmental outcomes of very low birth Weight infants enrolled in a randomized controlled trial of delayed versus immediate cord clamping. J Perinatol. 2010;30(1):11-16.
13. Sommers R, et al. Hemodynamic effects of delayed cord clamping in premature infants. Pediatrics. 2012;129(3):2667-e672.
14. Mathew J. Timing of umbilical cord clamping in term and preterm deliveries and infant and maternal outcomes: A systematic review of randomized controlled trials. Indian Pediatr.2011;48123-29.
15. Leduc D, et al. Active management of the third stage of labor prevention and treatment of postpartum hemorrhage. J Obstet Gynaecol Can. 2009;31(10):980-993.