Late cord clamping may benefit infants, review suggests



Compared with infants who had clamping of the umbilical cord within 1 minute after birth, those who had late clamping had higher hemoglobin levels between 1 and 2 days after birth and were less likely to be iron deficient 3-6 months after birth. They also had higher birth weights.

Those are key findings from a systematic review published July 11 in the Cochrane Library. "A more liberal approach to delaying clamping of the umbilical cord in healthy term infants appears to be warranted, particularly in light of growing evidence that delayed cord clamping may be of benefit in the longer term in promoting better iron stores in infants, as long as access to treatment for jaundice requiring phototherapy is easily accessible," wrote the researchers, who were led by Susan J. McDonald, Ph.D., professor of midwifery at La Trobe University/Mercy Hospital for Women, Melbourne.

The review, which supports a World Health Organization recommendation that the optimal time for cord clamping is between 1 and 3 minutes after birth, was carried out because active management, including early cord clamping, "is still widely practised in high-income countries, although relative timing of each individual component of the strategy varies," Dr. McDonald and her associates wrote. "Most maternity units in Australia and the United Kingdom administer the uterotonic prior to placental delivery, whereas some units in the United States and Canada advocate withholding uterotonic administration until after the placenta is delivered."

The researchers reviewed data on 3,911 women and their infants who participated in 15 trials that examined the effects of different timing of umbilical cord clamping in term infants (Coch. Database Syst. Rev. 2013 July 11 [doi:10.1002/14651858.CD004074.pub3]).

Early clamping was defined as that which occurred within 1 minute of the infant’s birth while late clamping was defined as that which occurred later than 1 minute after the infant’s birth. The researchers characterized the overall methodologic quality of the trials included in the review as "moderate or high. While none of the studies was assessed as being at high risk of bias for most domains, several trials did not provide clear information on methods."

Compared with infants in the late-clamping group, those in the early-clamping group demonstrated significantly lower hemoglobin concentrations at 24-48 hours (a mean deviation of –1.49 g/dL), a difference that was not seen at subsequent assessments. Infants in the early-clamping group were 2.65 times more likely to be iron deficient at 3-6 months, compared with their counterparts in the late-clamping group, while a significant birth weight increase was observed in the late- vs. the early-clamping group (a mean of 101 g). At the same time, significantly fewer infants in the early cord-clamping group required phototherapy for jaundice, compared with those in the late cord-clamping group (risk ratio, 0.62).

"The benefits and harms seen for delayed cord clamping are compatible with the same mechanism of an increased amount of red blood cells for the infant," the authors concluded. "Additional red blood cells can improve the infant’s iron stores, but this also has the potential to overload the newborn’s metabolism, leading to increased levels of bilirubin and, in very severe cases, severe jaundice and later kernicterus. The potential for harm would need to be weighed up by clinicians in context with the settings in which they work. For instance, if treatment for moderate to severe jaundice was not easily accessible and there was a risk of causing further complications for the infant, late cord clamping may be less optimal. On the other hand, increasing iron stores in infants through delayed cord clamping may be particularly beneficial in resource-poor settings where severe anemia is common."

They acknowledged certain limitations of the review, including differences in variables such as the lengths of timing for both early- and late cord clamping, as well as the inconsistent coverage of outcomes between trials. "In addition, the use of prophylactic uterotonics was not always well described in the trials," they wrote.

The review was supported by the Department of Health and Aging, Australia; the National Institute for Health Research, United Kingdom; and the National Health and Medical Research Council, Australia.

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