Commentary for the manuscript titled "Late vs. early clamping of the umbilical cord in full-term neonates" provided by Xi-Kuan Chen and Dr. Mark Walker
This is a well-designed systematic review of controlled trials to compare the potential effects of late cord clamping (≥2 minute) on infant hematological status, iron status, and risk of adverse events (jaundice, polycythemia, and respiratory distress) compared with early clamping (<2 minute) of cord in full-term neonates. This study included the detailed description of the literature search strategy and how the validity of individual studies was assessed. Due to the different definition of early cord clamping, the authored undertook a sensitivity analysis to further validate the findings. The main research results were consistent from study to study. The aggregate data were used in the data analysis. The meta-analysis included 15 controlled trials and 1912 newborns. The late cord clamping were associated with improved hematologic status (hematocrit level), iron status (ferritin concentration and stored iron), and with a reduced risk of clinical anemia. Neonates with late claming were associated with increased risk of asymptomatic polycythemia. This study has several strengths. This study was restricted in full-term neonates, which could control the confounding roles of preterm birth. The study outcomes not only cover some laboratory test values, but also some clinical outcomes. This study also has some limitations which should not be overlooked. First, the majority of studies included in this systematic review did not contain the information on hematological status of the recruited mothers such as maternal anemia, or iron-fortified status, which might be importantly potential confounders in the observed association. Second, the majority of studies included in this review defined early cord clamping as clamping within the first 10 seconds. Most included studies defined late cord clamping either after cessation of cord pulsation or at 3 minutes. This systematic review defined late clamping as 2 minutes. That is, those subjects with clamping between 2 and 3 minutes would be treated differently, because there was no detailed information on individual clamping time. Some of them were included in the late clamping group (reference No. 32), if the original study defined late clamping as 2 minutes. Some of them were not included in both groups (Reference No. 37), if the original studies define late clamping as 3 minute or later. Third, some outcomes were estimated based on only 1 or small number of the trials, which would influence the reliability of reported association. Fourth, in this systematic review, not all included trials were randomized. However, the authors stratify the analysis as randomized controlled trials and nonrandomized controlled trials could minimize the influence of including nonrandomized trials in the study. Finally, all included trials in this systematic review were English language, which might lead to English language bias. Based on this meta-analysis, late clamping of the umbilical cord is an efficient and effective means of improving hematologic status, enriching iron stores and ferritin levels and preventing anemia, which is likely to have an important impact on clinical practice. Although further research may be needed to determine the minimum time required to provide maximum benefit of placental transfusion, this meta-analysis encourages a late clamping of the umbilical cord in full-term neonates.
Dear Xi-Kuan
Thank you very much for your presentation. From your point of view, Do you think that late clamping should be a routine management (guideline) in a term neonate. Would be any condition of contraindication of this practice? Is asymptomatic polycythemia reverted spontaneously?
Thank you very much
Rocio Monroy
Commentary for the
Commentary for the manuscript titled "Late vs. early clamping of the umbilical cord in full-term neonates" provided by Xi-Kuan Chen and Dr. Mark Walker
This is a well-designed systematic review of controlled trials to compare the potential effects of late cord clamping (≥2 minute) on infant hematological status, iron status, and risk of adverse events (jaundice, polycythemia, and respiratory distress) compared with early clamping (<2 minute) of cord in full-term neonates. This study included the detailed description of the literature search strategy and how the validity of individual studies was assessed. Due to the different definition of early cord clamping, the authored undertook a sensitivity analysis to further validate the findings. The main research results were consistent from study to study. The aggregate data were used in the data analysis. The meta-analysis included 15 controlled trials and 1912 newborns. The late cord clamping were associated with improved hematologic status (hematocrit level), iron status (ferritin concentration and stored iron), and with a reduced risk of clinical anemia. Neonates with late claming were associated with increased risk of asymptomatic polycythemia. This study has several strengths. This study was restricted in full-term neonates, which could control the confounding roles of preterm birth. The study outcomes not only cover some laboratory test values, but also some clinical outcomes. This study also has some limitations which should not be overlooked. First, the majority of studies included in this systematic review did not contain the information on hematological status of the recruited mothers such as maternal anemia, or iron-fortified status, which might be importantly potential confounders in the observed association. Second, the majority of studies included in this review defined early cord clamping as clamping within the first 10 seconds. Most included studies defined late cord clamping either after cessation of cord pulsation or at 3 minutes. This systematic review defined late clamping as 2 minutes. That is, those subjects with clamping between 2 and 3 minutes would be treated differently, because there was no detailed information on individual clamping time. Some of them were included in the late clamping group (reference No. 32), if the original study defined late clamping as 2 minutes. Some of them were not included in both groups (Reference No. 37), if the original studies define late clamping as 3 minute or later. Third, some outcomes were estimated based on only 1 or small number of the trials, which would influence the reliability of reported association. Fourth, in this systematic review, not all included trials were randomized. However, the authors stratify the analysis as randomized controlled trials and nonrandomized controlled trials could minimize the influence of including nonrandomized trials in the study. Finally, all included trials in this systematic review were English language, which might lead to English language bias. Based on this meta-analysis, late clamping of the umbilical cord is an efficient and effective means of improving hematologic status, enriching iron stores and ferritin levels and preventing anemia, which is likely to have an important impact on clinical practice. Although further research may be needed to determine the minimum time required to provide maximum benefit of placental transfusion, this meta-analysis encourages a late clamping of the umbilical cord in full-term neonates.
Dear Xi-Kuan Thank you very
Dear Xi-Kuan
Thank you very much for your presentation. From your point of view, Do you think that late clamping should be a routine management (guideline) in a term neonate. Would be any condition of contraindication of this practice? Is asymptomatic polycythemia reverted spontaneously?
Thank you very much
Rocio Monroy