Waiting up to 2 minutes after delivery to cut the umbilical cord led to increased iron status at 6 months, with no adverse associations for mothers or infants, and could be valuable in preventing developmental delays associated with iron deficiencies, according to findings from a large randomized controlled trial.
Dr. Camila M. Chaparro of the University of California, Davis, and colleagues reported results from 358 mother-and-singleton infant pairs delivered at a large obstetric hospital in Mexico City. The primary outcomes were infant blood and iron status at age 6 months—the longest follow-up to date in any trial of delayed cord clamping (Lancet 2006;367:1997–2004).
The investigators randomized mothers to one of two groups: In one group, the umbilical cord was clamped after 10 seconds. In the other group, it was clamped after 2 minutes—coinciding roughly with the usual cessation of cord pulsations—unless the physician determined earlier cord removal was necessary. Ultimately, the mean clamping time for the early-clamping group was roughly 17 seconds, compared with about 94 seconds for the delayed-clamping group—a difference of just over 1 minute.
At 6 months of age, the delayed-clamping infants had significantly higher levels than the early-clamping infants in several measures (adjusted for maternal factors): stored iron (58 mg vs. 31 mg), body iron (343 mg vs. 316 mg), mean corpuscular volume (81.0 fL vs. 79.5 fL), and ferritin (50.7 mcg/L vs. 34.4 mcg/L). Moreover, the incidence of iron deficiency (less than 9 mcg/L) in the early-clamping infants was 7%, compared with 1% in the delayed-clamping group, and unadjusted incidence of iron-deficiency anemia was 4% in early-clamping infants vs. 0% in the delayed-clamping group, the investigators noted.