Effect of timing of umbilical cord clamping on iron status in Mexican infants: a randomised controlled trial.
BACKGROUND
Delayed clamping of the umbilical cord increases the infant's iron endowment at birth and haemoglobin concentration at 2 months of age. We aimed to assess whether a 2-minute delay in the clamping of the umbilical cord of normal-weight, full-term infants improved iron and haematological status up to 6 months of age.


METHODS
476 mother-infant pairs were recruited at a large obstetrics hospital in Mexico City, Mexico, randomly assigned to delayed clamping (2 min after delivery of the infant's shoulders) or early clamping (around 10 s after delivery), and followed up until 6 months postpartum. Primary outcomes were infant haematological status and iron status at 6 months of age, and analysis was by intention-to-treat. This study is registered with ClinicalTrials.gov, number NCT00298051.


RESULTS
358 (75%) mother-infant pairs completed the trial. At 6 months of age, infants who had delayed clamping had significantly higher mean corpuscular volume (81.0 fL vs 79.5 fL 95% CI -2.5 to -0.6, p=0.001), ferritin (50.7 mug/L vs 34.4 mug/L 95% CI -30.7 to -1.9, p=0.0002), and total body iron. The effect of delayed clamping was significantly greater for infants born to mothers with low ferritin at delivery, breastfed infants not receiving iron-fortified milk or formula, and infants born with birthweight between 2500 g and 3000 g. A cord clamping delay of 2 minutes increased 6-month iron stores by about 27-47 mg.


CONCLUSIONS
Delay in cord clamping of 2 minutes could help prevent iron deficiency from developing before 6 months of age, when iron-fortified complementary foods could be introduced.
Chaparro
Camila M
CM
Department of Nutrition, Program in International and Community Nutrition, University of California, Davis, CA 95616-8669, USA.
Neufeld
Lynnette M
LM
Tena Alavez
Gilberto
G
Eguia-Líz Cedillo
Raúl
R
Dewey
Kathryn G
KG
D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000517:prevention & control*; D003250:Constriction; D005260:Female; D005293:Ferritins / Q000097:blood*; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007223:Infant; D007225:Infant Food; D007231:Infant, Newborn; D007501:Iron / Q000097:blood*; D008297:Male; D008800:Mexico; D013997:Time Factors; D014470:Umbilical Cord / Q000098:blood supply*
D005293:Ferritins; D007501:Iron