Cerclaje De Cordon Umbilical

REVIEW

CLINICIAN’S CORNER

Late vs Early Clamping of the Umbilical Cord in Full-term Neonates
Systematic Review and Meta-analysis of Controlled Trials
Eileen K. Hutton, PhD Eman S. Hassan, MBBCh umbilical cord at birth is by far the oldest and most prevalent intervention in humans. In spite of that, the optimal timing of cord clamping has been a controversial issue for decades.1-4 Thereare no formal practice guidelines, but most practitioners in western countries clamp and cut the cord immediately after birth, while the practice worldwide is variable.5,6 Earlier physiological studies have shown that, of the total blood volume in the combined fetal-placental circulation at full gestation, approximately 25% to 60% (54-160 mL) is found in the placental circulation and that as many as60% of the fetal red blood cells are found therein.7-10 This blood is also known to be rich in hematopoietic stem cells.9,11 Previous research has suggested that early clamping of the cord (within the first 5 to 10 seconds of birth), compared with later clamping, results in a decrease to the neonate of 20 to 40 mL of blood per kilogram of body weight,3,10,12,13 which would provide the equivalentof 30 to 35 mg of iron.14,15 It has been argued that early cord clamping puts the newborn at increased risk of hypovolemic damage
For editorial comment see p 1257. CME available online at www.jama.com Context With few exceptions, the umbilical cord of every newborn is clamped and cut at birth, yet the optimal timing for this intervention remains controversial. Objective To compare the potentialbenefits and harms of late vs early cord clamping in term infants. Data Sources Search of 6 electronic databases (on November 15, 2006, starting from the beginning of each): the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Neonatal Group trials register, the Cochrane library, MEDLINE, EMBASE, and CINHAL; hand search of secondary references in relevant studies; and contactof investigators about relevant published research. Study Selection Controlled trials comparing late vs early cord clamping following birth in infants born at 37 or more weeks’ gestation. Data Extraction Two reviewers independently assessed eligibility and quality of trials and extracted data for outcomes of interest: infant hematologic status; iron status; and risk of adverse events such asjaundice, polycythemia, and respiratory distress. Data Synthesis The meta-analysis included 15 controlled trials (1912 newborns). Late cord clamping was delayed for at least 2 minutes (n=1001 newborns), while early clamping in most trials (n=911 newborns) was performed immediately after birth. Benefits over ages 2 to 6 months associated with late cord clamping include improved hematologic statusmeasured as hematocrit (weighted mean difference [WMD], 3.70%; 95% confidence interval [CI], 2.00%-5.40%); iron status as measured by ferritin concentration (WMD, 17.89; 95% CI, 16.58-19.21) and stored iron (WMD, 19.90; 95% CI, 7.67-32.13); and a clinically important reduction in the risk of anemia (relative risk (RR), 0.53; 95% CI, 0.40-0.70). Neonates with late clamping were at increased risk ofexperiencing asymptomatic polycythemia (7 studies [403 neonates]: RR, 3.82; 95% CI, 1.11-13.21; 2 highquality studies only [281 infants]: RR, 3.91; 95% CI, 1.00-15.36). Conclusions Delaying clamping of the umbilical cord in full-term neonates for a minimum of 2 minutes following birth is beneficial to the newborn, extending into infancy. Although there was an increase in polycythemia among infants inwhom cord clamping was delayed, this condition appeared to be benign.
JAMA. 2007;297:1241-1252 www.jama.com

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LAMPING AND CUTTING OF THE

and iron loss, as well as of several blood disorders and type 2 diabetes, as a consequence of loss of hematopoietic stem cells.3,16,17 Early cord clamping has been postulated as a major cause of anemia in infancy, and this has led some investigators to...