REVISTA
PAULISTA
DE
PEDIATRIA
www.rpped.com.br
ORIGINAL
ARTICLE
Excessive
weight
loss
in
exclusively
breastfed
full-term
newborns
in
a
Baby-Friendly
Hospital
Maria
Aparecida
Mezzacappa
∗,
Bruna
Gil
Ferreira
FaculdadedeCiências,UniversidadeEstadualdeCampinas(Unicamp),Campinas,SP,Brazil
Received21July2015;accepted14October2015 Availableonline15March2016
KEYWORDS Newborn; Breastfeeding; Weightloss; Cesareansection
Abstract
Objective: To determine the risk factors for weight loss over 8% in full-term newborns at postpartumdischargefromaBabyFriendlyHospital.
Methods: The cases were selected from acohort ofinfants belonging to aprevious study. Healthyfull-termnewbornswithbirthweight≥2.000g,whowereexclusivelybreastfedwere includedandexcludedtwinsandthoseundergoingphototherapyaswellasthosedischarged after 96hoflife.The analyzedmaternal andneonatalvariableswere maternal age,parity, ethnicity,typeofdelivery,maternaldiabetes,gender,gestationalageandappropriateweight for age.Adjusted multipleandunivariateCoxregressionanalyseswereused,consideringas significantp<0.05.
Results: Westudied414newborns,ofwhom107(25.8%)hadexcessiveweightloss.Through theunivariateregression,riskfactorsassociatedwithweightloss>8%werecesareandelivery andoldermaternalage.Attheadjustedmultipleregressionanalysis,themodeltoexplainthe weightlosswascesareandelivery(Relativerisk2.27,95%ofConfidenceInterval1.54---3.35).
Conclusions: Theindependentpredictorforweightloss>8%inexclusivelybreastfedfull-term newborns inaBaby-FriendlyHospitalwasthecesarean delivery.Itispossibletoreducethe numberofcesareansectionstominimizeneonatalexcessiveweightlossandtheresultinguse ofinfantformuladuringthefirstweekoflife.
©2015SociedadedePediatriadeS˜aoPaulo.PublishedbyElsevierEditoraLtda.Thisisanopen accessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).
∗Correspondingauthor.
E-mail:[email protected](M.A.Mezzacappa). http://dx.doi.org/10.1016/j.rppede.2016.03.003
PALAVRAS-CHAVE Recém-nascido; Amamentac¸ão; Perdadepeso; Cesárea
Perdadepesoexcessivaemrecém-nascidosatermoamamentadosexclusivamente aoseiomaternoemumHospitalAmigodaCrianc¸a
Resumo
Objetivo: Determinarosfatoresderiscoparaperdadepesoacimade8%emrecém-nascidoa termoporocasiãodaaltapós-partodeumHospitalAmigodaCrianc¸a.
Métodos: Oscasosforamselecionadosdeumacoortederecém-nascido, pertencentesaum estudoprévio.Foramincluídosrecém-nascidosatermocompesoaonascer≥2.000g,saudáveise amamentadosexclusivamente,excluídososgemelares,osrecém-nascidosqueusaram fototera-pia eaquelescomalta hospitalarapós96horasdevida. Asvariáveismaternaseneonatais estudadasforamidadematerna,paridade,rac¸a,tipodeparto,diabetematerna,sexo,idade gestacionaleadequac¸ãodopesoparaidade.ForamusadasasanálisesderegressãodeCox univariadaemúltiplaajustadasefoiconsideradosignificativop<0,05.
Resultados: Foramestudados414recém-nascidosdosquais107(25,8%)tiveramperdaexcessiva depeso.Pelaregressãounivariada,osfatoresderiscoassociadosàperdadepeso>8%foram partocesáreaemaioridadematerna.Pelaanálisederegressãomúltiplaajustada,omodelo paraexplicaraperdadepesofoiopartocesárea(RiscoRelativo:2,27eIntervalodeConfianc¸a 95%:1,54---3,35).
Conclusões: Opreditorindependenteparaperdadepesomaiordoque8%emrecém-nascidosa termoamamentadosexclusivamenteemumHospitalAmigodaCrianc¸afoiacesárea.Épossível queareduc¸ãodonúmerodecesáreaspossaminimizaraperdadepesoneonatalexcessivaeo consequenteusodefórmulalácteanaprimeirasemanadevida.
©2015SociedadedePediatriadeS˜aoPaulo.PublicadoporElsevierEditoraLtda.Esteéumartigo OpenAccesssobalicençaCCBY(https://creativecommons.org/licenses/by/4.0/deed.pt).
Introduction
Almostallnewborns loseweightonthefirstdaysof life.1
Giventhishighfrequency,theauthorscallitphysiological weightloss.2Moststudiessuggestthatthelosscorresponds
mainly to fluid reduction,1 but it is also a consequence
ofthe use of adiposetissue asasource of energyby the newborns.2
Onthefirst2---3daysoflife,3newborns thatare
exclu-sivelybreastfedloseonaveragebetween5%and7%oftheir birthweight.1The maximumphysiologicallimitsofweight
loss for newborns that are exclusively breastfed are con-troversial. Thus, a weight loss of 10% can be considered normalor acceptable,4---6 although therehave been
refer-encesabout7%values.7
Theevolutionofthenewborn’sweightonthefirstdays oflifeis usedasanindicator ofbreastfeedingadequacy.7
Thus,thepercentageofweightreductioninrelationtobirth weightcanbeoneoftheparametersusedforthe introduc-tionofformula.8
Thesubjecthasattractedincreasinginterestduetothe largenumberofaspectswithlowlevelsofevidence. How-ever,thepercentageofweightlossthatindicatesformula supplementation,the decreasein weightcompatiblewith safe hospital discharge and the time required for weight recoveryremaintobedefined.9
UNICEF’sBabyFriendlyHospitalinitiative10recommends
exclusivebreastfeeding,buttheshort-termimpactofthis practiceonweightevolutionislittleknown.
Regarding the possible markers associatedwith weight loss, there are publications involving infants with partial feeding, i.e., babies that are breastfed and also receive
formulasupplementation.11,12 Inthesestudies,thefactors
associatedwithweightlossaremultipleandamongthemis thecesareandelivery.Ontheotherhand,therehavebeen few studies in newborns thatare exclusivelybreastfed3,13
andinBaby-FriendlyHospitals.14,15Theaimofthisstudywas
todetermine therisk factors forweightloss greater than 8%infull-termnewbornsthatareexclusivelybreastfedina Baby-FriendlyHospital.
Method
A secondary analysis wasperformed on data from a pre-viously published study (n=608) carried out from06/2008 to 10/2008.16 The weight gain of a cohort of full-term
newborns with birth weight ≥2.000g and≥37 weeks ges-tational age was prospectively assessed at birth and at hospitaldischarge.Newbornsthatreceivedformula supple-mentation or exclusive formula, twins, newborns whose discharge occurred after 96h of life and those submit-tedtophototherapyduringhospitalizationafterbirthwere excluded.
Thenewbornswereweighedatbirthandonthedayof discharge,withoutclothes, usingaFilizolaTMscale,witha
sensitivity of 5g.The study site is a public, tertiary hos-pital,whichhasadheredtothe10recommendedstepsand receivedthetitleofaBaby-FriendlyHospital12yearsago.10
The following maternal independent variables were assessed: age, ethnicity, parity, type of delivery and his-toryofdiabetes,basedontheresultsoftheglucosecurve duringtheprenatalperiod.Amongtheneonatalvariables, thefollowingwereassessed:gender,birthweight,adequate weightfor age,weightat dischargeandhospitallengthof stay.Theweightatdischargewasobtainedinthemorningof thedischargeday.Gestationalage17 wasestablishedinthe
delivery roomandthe adequacyof weightfor gestational agewasdefinedaccordingtotheintrauterinegrowthcurve ofAlexanderetal.,18usingthebirthweight.Weightlossin
percentage,atthetimeofhospitaldischarge,was consid-eredasthepercentagedifferencebetweenthebirthweight andtheweightmeasuredatdischarge.
Thedependentvariablewasexcessiveweightloss, con-sidered whenthere wasareduction >8% inweight at the hospitaldischargeinrelationtothebirthweight.
Theinformationonthevariableswasaddedtothe previ-ousstudydatabase16:adequacyofweightforageandhistory
of maternal diabetes. Data analysis was performed using theSASSystemforWindowsversion9.1.3.Statistical anal-ysiswasperformedusingchi-squaretest, Student’st-test, Kruskal---Wallistest,univariateandmultipleCoxregression, adjustedbythetimeofdischarge,asnewbornswithvaginal andcesareansectiondeliveryhaddifferenthospitallength ofstay.The variableselection processusedinthe regres-sionanalysiswasthestepwise, inwhich,at eachstep,all combinationsaretested.Allvariableswereenteredintothe model,regardlessofthep-valueintheunivariateanalysis. Relativerisk(RR)valuesand95%confidenceinterval(95%) wereestablishedandvalueswereconsideredsignificantfor
p<0.05.
The Institutional Review Board of the institution approvedthe originalproject andwaived consentfor this secondaryanalysisstudy.
Results
The study included 414 newborns, according tothe crite-ria of inclusion and exclusion explained in the Method’s section and in Fig. 1. In relation to birth weight, the mean±SDwas3.319±409g,themedianwas3.305gandthe interquartile range was 3.005---3.595g. The mean weight lossinthissamplewas6.4±2.5%.Ofthetotal,107(25.8%) showedexcessiveweightloss,withameanlossof9.4%±1.1%
Original cohort n=608 NB
Excluded
Discharge after 96h n=78 NB
Phototherapy n=12 NB
Twins n=8 NB
Current Study n=414 NB
Included GA≥37 weeks
Exclusive breastfeeding
n=512
Figure1 Cohortcompositionbasedontheoriginalstudy.
(range:8.1---13.6%). In 20 newborns (4.8%) weight loss at dischargewashigherthan10%.Hospitallengthofstaywas significantlydifferentbetweenthegroupswithandwithout excessiveweightloss;hospitaldischargeoccurred, respec-tively, after 61.4±9.9h vs. 58.0±9.8h (p=0.003). Table 1
shows the distribution of mean weight loss and the fre-quencyofweightloss>8%,accordingtothegestationalage. Weight loss did not differ between the gestational ages. Thefrequencyofcesareansectionwassignificantlydifferent (p<0.001)amongthegestationalages(Table1).
Table2shows therisk factorsat theunivariate regres-sion. Risk factors associated with weight loss >8% were cesarean delivery and older maternal age (Table 2). The model obtained by multiple regression analysis adjusted for the time of discharge that offered the best explana-tionforweightlossinthissamplecorrespondedtocesarean
Table1 Mean±SDandmedianweightlossvaluesathospitaldischargeandtherelativefrequencyofcesareandeliveryand weightlossover8%,accordingtogestationalage(n=414).
GA n Cesarean%a Mean±SD Medianb Loss>8%(%)
37 50 56.2 6.9±2.8 7.2 34.0
38 59 18.0 6.1±2.4 6.5 22.0
39 104 44.4 5.9±2.5 6.1 20.2
40 141 54.9 6.7±2.4 6.8 30.5
41 60 46.3 5.8±2.4 6.4 21.7
GA,gestationalage;n,numberofcases;%,percentage;SD,standarddeviation.
a p<0.001atthechi-squaretest.
Table2 Riskfactorsforweightloss>8%athospitaldischargeinfull-termnewbornsreceivingexclusivebreastfeeding,according totheadjustedunivariatelogisticregressionanalysis(n=414).
>8%
n=107
≤8%
n=307
p-valuea RRb 95%CIb
Maternalage(years;mean±SD) 26.4±6.2 24.6±6.3 0.034 1.03 1.00---1.06 Parity(mean±SD) 0.8±0.9 0.9±1.2 0.335 0.91 0.76---1.09 Blackethnicity,cn(%) 36(33.6) 124(40.3) 0.163 0.75 0.50---1.12
Maternaldiabetes,n(%) 4(3.7) 4(1.3) 0.263 1.77 0.65---4.84 Cesareandelivery,n(%) 54(50.4) 74(24.1) <0.0001 2.16 1.47---3.18 Femalegender,n(%) 56(52.3) 144(46.9) 0.397 1.17 0.80---1.72 GA37weeks,dn(%) 17(15.8) 33(10.7) 0.488 1.12 0.65---1.94
Birthweight(g;mean±SD) 3337±415 3313±407 0.778 1.00 1.00---1.00
AGA,en(%) 89(83.1) 258(84.0) 0.375 0.77 0.38---1.53
SD,standarddeviation;g,grams;n,numberofcases;GA,gestationalage;AGA,appropriateforgestationalage.
ap-valuebyunivariateCoxregressionadjustedtohoursoflifeathospitaldischarge.
b RR,relativerisk;95%CI,95%confidenceinterval.
c 21newbornswithoutinformationonmaternalethnicity.
d RRof37weekvs.≥40week.
e RRofAGAvs.smallforage.
section,whichindependentlyincreasedtheriskofloss>8% by2.27-fold(RR2.27,95%CI1.54---3.35;p<0.0001).
Discussion
Risk factors for excessive weight loss in full-term infants thatwereexclusively breastfedandwere bornin a Baby-FriendlyHospitalwerecesareansectionandoldermaternal age. At the multiple regression model, cesarean deliv-ery remained the only independent factor for weight loss>8%.
Considering the policiesof the Baby-FriendlyHospital, the mean loss observed in the total sample was similar to that in other studies. Thus, the mean weight loss of 6.4% is compatible with descriptions of 5.7% to 6.6%±2% in a systematic review of 11 very heterogeneousstudies, withexclusivelybreastfednewborns andregardlessofthe typeofdelivery.2,14Asforthefrequencyofweightloss>8%
in this study, it wasa significant one (25.8% of the new-borns).Differentdefinitionsof excessiveweightloss have beenusedbyauthors,namely>7;>8and>10%.19The8%
cut-offisnotveryfrequentlyused.19Wefoundonereference14
thatdescribed values of7.4% of newborns withlosses>8% onexclusivebreastfeeding,notbreastfeedingandformula. Wechosethe8%thresholdforexcessiveweightloss consid-eringtheneedforbreastfeedingsupplementationinthese infantsafterhospitaldischarge,asshowninstep10ofthe Baby-FriendlyHospital.8,10
There is no consensus whether a weight loss>7% can indicatebreastfeedingproblems7,8and,ontheotherhand,
the loss of 8---10% can be considered physiological if there are no abnormalities at the physical examination. It indicates, however, the need for greater breastfeeding support.8,19
Forlosses>10%,thevalueobtainedinthisstudyiscloseto thelowerlimitofthewiderangeofvariationfoundinother publications.4,5,11,15,20---22Thus,2.45to25%21ofnewbornslose
morethan 10%of weightaccording tostudieswith differ-enttypesoffeeding.Theabsenceofnewbornswithweight loss>10% has alsobeen described.3,14 Webelieve the
per-centageof4.8%obtainedinthisstudycanbeattributedto theimplementationofallstepsoftheBaby-FriendlyHospital Initiativeintheservice.
Amongtheassessedriskfactors,oldermaternalagewas identifiedasapredictorofweightloss,probablybecause, witholderage,thereis anincreaseinmaternal morbidity duetohypertensionanddiabetes,whichdevelopsintothe riskofdeliverybycesareansection.23
At the bivariate analysis between gestational age and weightlossandbetweenageandthecesareanrate,a sig-nificant differencewasidentifiedonlyfor thesecond: the newbornswith37and40weeksofgestationalageshowed the highest frequencies of cesarean delivery. In turn, the multivariateregressionanalysis,whichsuppressedthe con-founding effects, did not show gestational age as a risk factor,whichwouldbeexpected,as,inclinicalpractice,the 37-weeknewbornsaretheonesthatshowgreaterpropensity tobreastfeedingdifficulties.24
Thebest-knownmechanismthatexplainstheassociation between cesarean delivery andgreater weightlossof the newbornandbreastfeedingproblemsisthedelayin lactoge-nesisII,definedascopiousmilkproductionthatstartsonthe 2nd/3rddayafterbirth.11,25Therearealsoknownnewborn
positioningimpedimentsinacesareandeliverytomeetstep 4oftheBaby-FriendlyHospital,withthefirstfeeding occur-ringwithinhalftoonehouroflife,whichmightcontribute toadelayedlactogenesis.26
Morerecently,studieshaveidentifiedthatanother mech-anism that would also be present is the excess of fluids administered tothemotherduring labor.22,27 The infusion
of1.200mLtomorethan2.500mLoffluids tothemother, at acesarean sectionor vaginaldeliverywithanalgesia,19
determineshypervolemiainnewbornsandincreases diure-sisonthefirstdayoflife.2,27Muchoftheweightlossofthese
subject19 evidencewasfound in eightstudies that
associ-atedweightlosswithexcessfluidsofferedtothemotherin exclusivelybreastfednewborns.Ontheotherhand,a ran-domizedclinical trial found noassociation between lower weightlossandfluidinfusionrestrictioninmothers.28
This study constitutes a secondary data analysis of a prior study, of which information about weight gain was prospectively collected. Thus, the evaluation of other variables associated with weight loss and breastfeeding difficulties13,20 wasnotperformed,whichcanbeseenasa
studylimitation.Also,thelongerdurationofhospitallength of stay aftera cesarean delivery whencomparedto vagi-naldeliverywouldpredisposetotheobservationofweight lossnadirinthisfirstgroup.21However,thiseffectwas
sup-pressedbyadjustingtheregressionanalysisfor thelength ofstayinhours.
The weight at hospital discharge wasthe predictor of thedegreeofanxiety andconcernabout themilk produc-tionvolume.20 Thus,ifitispossibletoknowandminimize
thefactorsassociatedwithweightloss,perhapsitmayalso bepossible to reduce maternal anxiety andcontribute to highersuccessratesofexclusivebreastfeeding.20 Itis
con-cludedthatreducingthenumberofcesareansectionscould minimizeexcessiveneonatalweightloss,andconsequently, minimizetheindicationofsupplementationwithformulaon thefirstdaysoflife.
Funding
ScientificInitiationGrantofProgramaInstitucionaldeBolsas deIniciac¸ãoCientífica(Pibic),ConselhoNacionalde Desen-volvimentoCientíficoeTecnológico(CNPq).
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
Acknowledgements
To Cleide Aparecida Moreira Silva, from the Biostatistics Service of Câmara de Pesquisa FCM/Unicamp/Campinas/Brazil,forthestatisticalanalysis.
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