Delayed umbilical cord clamping for at least 60 seconds after birth significantly reduced death or disability in infants of less than 30 weeks’ gestation, according to data from nearly 1,500 infants.
The burden of disability and mortality for babies born before 30 weeks’ gestation remains high, especially in low- and middle-income countries, wrote Kristy P. Robledo, PhD, of the University of Sydney, Australia, and colleagues. Delayed clamping of the umbilical cord is a simple procedure that may improve mortality in this population, but more research is needed; recommended times to delayed clamping range from 30 seconds to 3 minutes, they noted.
In a study published in, the researchers randomized 767 very preterm infants to delayed clamping at least 60 seconds after birth and 764 to immediate clamping. Of these, 384 were multiple births (who were individually randomized), 862 were male, and 505 were born before 27 weeks’ gestation. The primary outcome was death or disability at 2 years of age. Major disability was defined as cerebral palsy, severe visual loss, deafness requiring a hearing aid or cochlear implants, major language or speech problems, or cognitive delay at 2 years corrected age. The median time to clamping was 60 seconds in the delayed group and 5 seconds in the immediate group.
Primary outcome data were available for 1,419 infants. Death or major disability occurred in 29% of infants assigned to delayed clamping compared to 34% of those assigned to immediate clamping (relative risk 0.83, P = .010). The infants were part of the APTS Childhood Follow-Up Study, an open-label superiority trial conducted in Australia and New Zealand.
By age 2 years, 8% of infants in the delayed group and 11% of those in the immediate group had died; 23% and 26%, respectively, met criteria for major disability. The impact of delayed clamping translates to a 30% reduction in relative risk of mortality at 2 years of age, but no significant impact on major disability, the researchers wrote.
The findings were limited by several factors including the unblinded study design, lack of data on heart rate or time to first breath, and the clamping prior to 60 seconds in 26% of infants in the delayed group based on clinical concerns for these specific infants, the researchers noted.
However, the results were strengthened by the large size, low risk of bias, and specific primary outcome, they said. The data support findings from recent systematic reviews and highlight the need for further trials to evaluate delayed clamping at different time points, with larger populations, inclusion of time to first breath and heart rate, and improved measures of disability, the researchers added.
In clinical practice, “Given that aiming to delay cord clamping for 60 seconds or more improved 2-year outcomes and short-term hematological measures with no evidence of significant harm, it seems reasonable to conclude that delayed clamping is appropriate as standard care in very preterm infants,” they concluded.
Accepting simple intervention could have great impact
This study is important in light of the overwhelming burden of preterm birth on the health care system and society as a whole, Lisette D. Tanner, MD, of Emory University, Atlanta, said in an interview.
“Preterm birth is associated with billions in health care costs each year, and a large portion of that money is directed to the complications associated with preterm birth, such as early intervention services, educational support, and ongoing medical care,” Dr. Tanner said. “This study is particularly timely, as we are quickly approaching 2030, the deadline for achieving the United Nations Sustainable Development Goal of ending preventable deaths of newborns and children under 5 years of age,” she said. The goal involves “all countries aiming to reduce neonatal mortality to at least as low as 12 per 1,000 live births and under-5 mortality to at least as low as 25 per 1,000 live births. Effective treatments to reduce infant and child mortality would make strong inroads toward this goal,” she explained.
Dr. Tanner said she was not surprised by the findings because previous studies have shown similar results. “However, the large, multicenter nature of this study provides additional weight to recommendations to delay cord clamping as standard practice,” she said.
“The findings of this study support the recommendations of a number of large organizations,” said Dr. Tanner. “The World Health Organization recommends that the umbilical cord not be clamped earlier than 1 minute after birth in term or preterm infants who do not require positive pressure ventilation. The American College of Obstetricians and Gynecologists and the American Academy of Pediatrics now recommend a delay in umbilical cord clamping in vigorous term and preterm infants for at least 30–60 seconds after birth,” she said. “The Royal College of Obstetricians and Gynaecologists also recommends deferring umbilical cord clamping for healthy term and preterm infants for at least 2 minutes after birth,” she added.
However, “the delay in adoption of this guidelines in practice appears to be related to some concerns regarding universal adoption of this approach,” Dr. Tanner noted. “Some clinicians have suggested that delayed cord clamping could delay vital neonatal resuscitative efforts, leading to worse neonatal outcomes, but this concern has not been borne out in the data, as all guidelines specifically state that this intervention is for vigorous newborns,” she said. “In fact, in preterm infants, delayed cord clamping is associated with improved transitional circulation, decreased need for blood transfusion, and lower incidence of necrotizing enterocolitis and intraventricular hemorrhage,” Dr. Tanner emphasized. “Additionally, concerns persist that delayed cord clamping could lead to excessive transfusion with resultant polycythemia. Again, no data have supported this claim to date,” she said.
“Finally, some clinicians are concerned that delayed clamping could lead to delay in addressing maternal complications of birth such as hemorrhage, but studies have shown the opposite; delayed umbilical cord clamping has not been associated with an increased risk of postpartum hemorrhage or increased blood loss at delivery, nor has it been with a difference in the need for blood transfusion,” said Dr. Tanner.
Ideally, practitioners will become more comfortable in delaying cord clamping as a routine practice as more data demonstrating the safety and benefit of this easy intervention are disseminated, she said.
Additional research delineating which gestational ages benefit most from delayed cord clamping would help direct education efforts to implement this intervention, Dr. Tanner noted.
The study was funded by the Australian National Health and Medical Research Council. The researchers and Dr. Tanner had no financial conflicts to disclose.