Does the timing of umbilical cord clamping at delivery affect an infant’s long-term iron status

OBG Management, 03/02/2012

One of the arguments against delayed clamping is that the practice raises the risks of respiratory symptoms, polycythemia, and hyperbilirubinemia, and increases the need for phototherapy. However, this study demonstrated that late clamping does not increase these risks.

Methods

  • The trial was conducted in a Swedish county hospital in an affluent, high–income population.
  • Four hundred full–term, singleton infants, born after low–risk pregnancy, were randomized to early or late cord clamping.
  • Intravenous oxytocin (10 IU) was given immediately after the cord was clamped.
  • The time from full delivery of the baby to the start of cord clamping was measured by an assistant to the midwife.
  • Blood samples were taken from the newborns 48 to 72 hours after delivery and again at 4 months of age.

Results

  • The infants’ hemoglobin concentration and packed RBC volume were higher 2 days after delivery in the delayed–clamping group, compared with early clamping, and this translated into improved iron stores at the 4–month follow–up.
  • Specifically, the rate of anemia at a median age of 2.4 days was 1.2% in the delayed–clamping group versus 6.3% for early clamping (P = .02; relative risk reduction 0.80; 95% confidence interval [CI], 0.22–0.95).
  • And the geometric mean serum ferritin concentration at 4 months of age was 45% higher in the delayed–clamping group (117 μg/L vs 81 μg/L; P < .001; 95% CI, 23%–71%).
  • Iron deficiency was significantly more prevalent in the early–clamping group, but the prevalence of anemia was similar between groups.
  • To prevent one case of iron deficiency—with or without anemia—the number needed to treat was 20 (95% CI, 17–67).

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