"A 2011 Swedish trial found that only 0.6 percent of full-term babies with a three-minute delay in cord clamping were iron deficient at 4 months of age, compared to 5.7 percent with immediate cord clamping. By 4 years of age, children with delayed cord clamping had modestly higher scores in fine motor and social skills , a difference particularly evident among boys, who may be more susceptible to iron deficiency. Other research, summarized in a 2013 systematic review of studies , has consistently found that waiting to cut the cord gives babies a boost in iron.
Iron deficiency is thought to affect about 8 to 14 percent of infants and toddlers in the United States; the prevalence is much greater in developing..."