Efecto del clampeo demorado del cordón umbilical en la ferritina sérica a los seis meses de vida. Estudio clínico controlado aleatorizado / The effect ofearly and delayed umbilical cord clamping onferritin levels in term infants at six months oflife. A randomized, controlled trial

RESUMEN

Introducción. El clampeo demorado del cordón umbilical aumentaría el depósito de hierro en lactantes. Para comprobar esta hipótesis medimos la ferritina sérica a los seis meses de vida en niños nacidos a término, participantes en un estudio controlado aleatorizado que evaluó el efecto del tiempo de clampeo del cordón en el hematócrito venoso y la evolución neonatal. Métodos. De 276 neonatos incluidos en el estudio original, 255 (92,4%) fueron seguidos seis meses, 86 tuvieron clampeo temprano, 83 al minuto y 83 al tercer minuto. La variable principal de resultado fue la concentración de ferritina sérica a los seis meses. Resultados. Las características de los grupos de madres y niños fueron similares. La ferritina fue significativamente más alta en los niños con clampeo al tercer minuto (33,2 μg/L) que en los de clampeo temprano (20,9 μg/L) (diferencia de medias geométrica 1,6; IC 95% 1,2-2,1). No hubo diferencia significativa entre clampeo al minuto (25,5 μg/L) y clampeo temprano. Tampoco hubo diferencia en los valores medios de hemoglobina, entre los grupos temprano [10,6 g/dl (DE 1,11)], al minuto [10,8 g/dl (DE 0,86)] y tres minutos [10,7 g/dl (DE 0,97)], respectivamente. La prevalencia de anemia ferropénica fue tres veces mayor en niños con clampeo temprano (7%) en comparación con los del tercer minuto (2,4%) (diferencias no significativas; RR 0,30; IC 95% 0,10-1,60). Conclusión. En niños nacidos a término, el clampeo del cordón umbilical a los tres minutos del nacimiento aumentó significativamente las concentraciones de ferritina a los seis meses de edad. No hubo diferencias significativas en los niveles de hemoglobina.

ABSTRACT

Background. Delayed umbilical cord clamping could increase iron stores and prevent iron deficieney in infants. To test this hypothesis we measured serum ferritin and hemoglobin levels at six months of age in term infants who had participated in a randomized controlled trial, assessing the effect of cord clamping timing on neonatal hematocrit values and clinical outcome. Main outcome measure. Serum ferritin level at six months of age. Methods. Out of the 276 mothers and their infants that participated in the initial study, 255 (92.4%) were followed up to six months and included in this study. Of these, 86 had their cords clamped within the first 15 seconds (early clamping), 83 at one minute, and 83 at three minutes. The pediatricians in charge of the evaluations during the follow-up period and personnel in charge of the biochemical tests were blinded to the assignment group. In all but 3 infants the ferritin levels and hemoglobin levels were measured at six months of age. Results. Mothers and infants in the three groups had similar baseline characteristics. Serum ferritin levels were significantly higher in the infants of the three minutes group than in the infants of the early group 33.2 μg/L vs. 20.9 ug/L(geometric mean ratio 1.6;95%CI 1.2 to 2.11) but no difference was observed in one minute group (25.5 μg/L) vs. early group. There were no significant differences inmeanhemoglobin values, 10.6 g/dl (SD 1,1); 10.8 g/dl (SD 0.9) and 10.7 g/dl (SD 1.0) between groups early, one minute, and three minutes, respectively. Although there were no significant differences between groups, the prevalence of iron deficiency anemia (hemoglobin < 10.5 g/dl and ferritin < 9 μg/L) was 3 times more frequent in early clampling group (7.2%) than in three minutes group (2.4%) (RR 0.30; IC 95% 0.10-1.60). Conclusions. Delayed umbilical cord clamping at three minutes significantly increases serum ferritin levels in infants at 6 months of age. No significant differences were found between groups in mean hemoglobin levels.