RevPaulPediatr.2015;33(3):258---259
www.rpped.com.br
REVISTA
PAULISTA
DE
PEDIATRIA
EDITORIAL
In
time:
how
and
when
should
we
clamp
the
umbilical
cord:
does
it
really
matter?
Em
tempo:
como
e
quando
deve
ser
feito
o
clampeamento
do
cordão
umbilical:
será
que
realmente
importa?
Nestor
E.
Vain
a,b,c,∗aFundaciónparalaSaludMaternoInfantil(FUNDASAMIN),BuenosAires,Argentina
bPediatrics,SchoolofMedicine,UniversityofBuenosAires,BuenosAires,Argentina
cNeonatology,HospitalsSanatoriodelaTrinidad,PalermoandSanIsidro,BuenosAires,Argentina
Received1June2015
There areseveral reasons toanswer yes. The first one is that it is among the most frequently performed medical (orparamedical)interventionsinhumanbeings:3,000,000 timesayearinBrazil,131,000,000timesayearintheworld (thatmeans250timesaminute). Therefore,evena mini-malinfluenceofthewayorofthetimingofcordclamping onthe infants’ health becomesimportant, because of its potentialmassiveimpact.AMEDLINEsearchwiththewords ‘‘umbilical cord clamping’’ demonstrates the interest on thissimple procedure (88 publications fromJanuary 2014 toApril2015).Inthelast2PASmeetings(USA),wheremost recentlyperformedor ongoing researchstudies relatedto newborns are reported, there were workshops and many presentationsaboutthisissue.
It is clear, from RCTsand meta-analyses, that delayed cordclamping (DCC) in term newborns, for at least 1min afterbirth,resultsinasignificantamountofbloodpassing fromtheplacentatotheinfant(placentaltransfusion):the infants’weightincreasesanaverageof101g(approximately 96ccofblood).Asaresult,hemoglobinishigher48hafter birth, andiron deficiency during infancy is less frequent.
DOIoforiginalarticle:
http://dx.doi.org/10.1016/j.rpped.2015.06.001
∗Correspondingauthor.
E-mail:nestorvain@gmail.com
DCCslightly increasestheneed forphototherapy. Thereis noevidenceofmaternalcomplications.1
Therefore, ILCOR and other medical associations rec-ommendDCC forvigorously bornterm infants.2 But,what
happens in realpractice? The impressions of many of us, andnumeroussurveyssuggestthatthecompliancewiththis recommendationislow.3,4 Why?Thereareseveralpossible
explanations.Manyphysiciansactasiftheywerealwaysina rush.Recently,alackofknowledgeaboutthe recommenda-tionhasbeenreported.5Someobstetriciansmaystillhave
fearsbasedonapreviouslyreportedincreasedriskof mater-nal hemorrhage (not supported by current literature).1 In
fewcasesthecordisclampedearlysobloodcanbecollected for banking(an unsupportedpracticewhen performedfor individual use). On the belief that gravity influences the volumeofplacentaltransfusion,anotherreason(orexcuse) is thatit isuncomfortable toholdthebabyfor 2 or3min at thelevelofthe vaginabeforethecordisclamped. We haverecentlydemonstratedthat,ifthebabyisheldbythe motheronherabdomenorchest,DCCresultsinaplacental transfusionequivalenttothat of infants heldat the level of the introitus.6 This way,DCC can beeasily performed,
permitting at the same time immediate maternal infant contact,which potentially enhancesbonding and success-fulbreastfeeding.Still,observationofinfants’positionand breathingduringthosefirstminutesisessential.7
However, should DCC be performed in all births? Althoughtheinformationisscarce,DCCappearstoalsobe
Intime:howandwhenshouldweclamptheumbilicalcord:doesitreallymatter? 259
effective in term infants born by cesarean section.8 In
premature infants, meta-analyses of several RCTs (which include a few very immature infants) have shown that DCC increases arterial blood pressure and decreases the use of vasopressors and blood transfusions, and the inci-denceofintraventricularhemorrhage(IVH).9Inpremature
infants it has been shown that umbilical cord milk-ing produces effects on placental transfusion similar to those of DCC.10 Its main potential advantage is that it
is a brief procedure which may decrease the risk of heat loss in immature infants when compared to DCC. However, in the way it was originally described, milk-ing generates a very rapid and large blood transfusion, which implies potentialrisks.11 Arecent Cochrane review
of 15 RCTs comparing early clamping vs. a group of either DCC or milking in premature infants demonstrates a decrease in necrotizing enterocolitis, IVH, and blood transfusions.12
Inthelast2years,severalinvestigationsinanimalsand physiologicstudiesinhumanshaveexploredinmoredetail thesequenceofeventsatthetimeofbirthinrelationtocord clamping.Ithasbeenshowninlambsthatwhenthecordis clampedbeforelungexpansion,thereisabriefand imme-diateriseinaorticandcarotidbloodpressure,followedby arapiddecreaseinleftventricularoutputandheartrate. Whenbreathingprecedescordclamping,thereisasmoother transitionandnobradycardia.13Someofthecomplications
ininfantswhowereresuscitatedatbirthcouldberelated to the difficult cardiovascular transition and hypovolemia occurringwhenthecordisimmediatelyclamped, superim-posedtopreexistingasphyxia.14Furthermore,inpremature
infants, rapid changes in blood pressure couldbe related toIVH.Theparadigmofimmediatecordclampingand sub-sequentventilationfornonbreathinginfantsiscurrentlya subjectofcontroversyandclinicalinvestigation.
Inmanyprematureinfantswhoareelectivelydelivered because of maternal or fetal risks, the onset of sponta-neousbreathingfrequentlyoccursafter30sorevenlonger periods.Inthosecases,wehavebeenroutinelyrequesting theobstetricianstoclampandcutthecordimmediately,so assisted ventilationcanstart. Butwhy? Iftheclampingof thecordisdelayedinthoseinfants,afunctioningplacenta continuestosupplygasexchange.Providedwecanprevent heatlosses,whyshouldwedoitthatway?Probably,themost realisticansweris,‘‘becausethatisthewaywehavealways done it’’.Ongoing studies onresuscitation at thebedside withanintactcord,aswell asphysiologicresearchin ani-malsandhumansmayprovideamorerationalanswer.Until then,wehavetolivewiththeuncertaintyofwhetherwhat wedoisappropriateornot.Seriousresearchincludingwell designedtrialsevaluatingunsupported,butfrequently per-formedprocedures,isthebasisforprogressinmanyareas ofmedicine,includingneonatalcareatthetimeofbirth.
Funding
Thisstudydidnotreceivefunding.
Conflicts
of
interest
Theauthordeclaresnoconflictsofinterest.
References
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