Researchers at Uppsala University (Sweden) and Umeå University (Sweden), conducted a randomized controlled trial involving 400 full term infants born after a low risk pregnancy, to examine the effects of delayed cord clamping on the iron levels of babies in a county hospital in Sweden. The infants were randomized to delayed umbilical cord clamping (more than three minutes after delivery) or early clamping (less than 10 seconds after delivery). The main outcome measures were hemoglobin and iron status at four months of age, with the power estimate based on serum ferritin levels. Secondary outcomes included neonatal anemia, early respiratory symptoms, polycythaemia, and need for phototherapy.

The results showed that the infants demonstrated no significant differences in hemoglobin concentration between the groups, but infants subjected to delayed cord clamping had a higher mean ferritin concentration and a lower prevalence of iron deficiency. As for secondary outcomes, the delayed cord-clamping group had lower prevalence of neonatal anemia at two days of age. There were no significant differences between groups in postnatal respiratory symptoms, polycythaemia, or hyperbilirubinaemia requiring phototherapy. The study was published in the November 15, 2011, issue of BMJ.

“As iron deficiency in infants even without anemia has been associated with impaired development, delayed cord clamping seems to benefit full term infants even in regions with a relatively low prevalence of iron deficiency anemia,” concluded lead author neonatologist Ola Andersson, MD, of Uppsala University, and colleagues.

Physiological studies have shown that there is a transfer from the placenta of about 80 ml of blood at one minute after birth, reaching about 100 ml at three minutes after birth. These additional volumes of blood can supply extra iron amounting to 40 mg/kg to 50 mg/kg of body weight. When this extra iron is added to the approximately 75 mg/kg of body iron that a full-term newborn is born with, the total amount of iron can reach 115 mg/kg to 125 mg/kg of body weight, which may help prevent iron deficiency during the first year of life. On the other hand, there is also evidence to suggest that delayed umbilical cord clamping and cutting may put newborns at a higher risk of polycythemia, hyperbilirubinemia, and other neonatal disorders.

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Uppsala University
Umeå University