By Dr. Namrata Todurkar
The timing for clamping of the umbilical cord after birth is a critical part of the resuscitation of new-born infants and is important to be discussed because it is applicable at all gestational ages. The established practice of clamping the umbilical cord immediately after the delivery of the new-born was a result of the practice of decreasing postpartum haemorrhage.
However, it was subsequently realized that immediate cord clamping was not required to reduce it. In fact, there is no high-level evidence supporting the use of immediate cord clamping, and such immediate cord clamping had never been subjected to any controlled trial earlier. Several studies suggest a benefit to delaying clamping of the umbilical cord at birth in both term as well as preterm infants. An ultrasound study of blood flow through the umbilicus showed arterial and venous flow may not stop for 3 minutes.
These findings have led to the endorsement of policies to delay cord clamping by both the American Academy of Paediatrics and the American College of Obstetricians and Gynaecologists who recommend a 30–60-second delay before the umbilical cord is clamped in all preterm deliveries, when feasible, to ensure that at-risk new-borns receive an adequate placental transfusion. The World Health Organization also recommends delaying cord clamping (DCC) for 30–60 seconds in all neonates.
Advantages of DCC:
Research demonstrates that providing additional placental blood by DCC was associated with less need for blood transfusion, better circulatory stability, less intraventricular haemorrhage (all grades), lower risk of necrotizing enterocolitis and increased survival. There is a significant amount of evidence to prove that DCC increases haemoglobin and iron stores in early infancy.
The blood volume of infants with early cord clamping averages 72 mL/kg, whereas the blood volume of infants with cord clamping delayed for 60 seconds averages 93 mL/kg. In follow-up studies of infants who underwent DCC versus immediate clamping, long-term benefits were noted at 18 to 22 months and 4 years of age with improved gross and fine motor scores and in social domains.
A multicentre randomized clinical trial of over 1500 neonates less than 30 weeks’ gestation was performed in Australia and New Zealand between 2009 to 2017. This study showed that clamping the umbilical cord at least 60 seconds after birth reduced the risk of death or major disability (cerebral palsy, major visual impairment, hearing loss, major language or speech problems and cognitive delay) at 2 years by 17% compared to those who had immediate cord clamping. This is the largest trial study delayed versus immediate cord clamping and reporting outcomes at 2 years.
Immediate cord clamping does not allow placental transfusion and negatively influences the transition of neonates to extra uterine life, especially in preterm neonates. However, if cord clamping is delayed, up to 25–50 mL of blood per kilogram is transfused into the neonate, representing an approximate 25%–50% increase in the total blood volume. With delayed cord clamping, there is an increase in the risk of mild polycythaemia (excess red blood cell mass) and an increase in risk of jaundice. However, there is no increased treatment for these conditions.
Effect of DCC on Umbilical cord blood banking:
In theory, the practice of delaying cord clamping by 60 seconds might result in insufficient umbilical cord blood remaining for banking. The Canadian Task Force on Preventive Health Care suggests that sufficient blood remains in the umbilical cord and placenta after delayed clamping for umbilical cord blood banking and that both techniques can generally be accomplished.
Cord milking is an alternative to DCC that is used when the cord must be cut immediately for medical reasons, often because the new-born is in need of immediate resuscitation as judged by the clinician overseeing the resuscitation. Immediate cord clamping might be necessary when there is abruption of placenta, monochorionic twin delivery (first born twin may be exchanging blood with the second twin) or if placenta has to be incised during delivery. Clinical trials have demonstrated that both DCC and cord milking in preterm new-borns increase pumping capacity of the heart, improve blood flow to major organs and enhance brain oxygen extraction.
Delayed cord clamping has become a standard practice worldwide for neonates of all gestational ages and has made it into the neonatal resuscitation program (NRP).
Dr. Namrata Todurkar, MBBS, MD (Pediatrics), DNB (Pediatrics). Fellowship in Neonatology from National Neonatology Forum India. Fellow in Neonatal-Perinatal Medicine at the University of British Columbia. Areas of interest: Neonatal nutrition, Fluid and Electrolyte Management, Inborn Errors, Neurodevelopmental follow-up of preterm infants. Dr. Todurkar is a volunteer blogger at CPBF.