Aromatherapy for pain management in labour

32 Pages·2014·0.25 MB·English

Aromatherapy for pain management in labour (Review)
SmithCA, Collins CT, Crowther CA
ThisisareprintofaCochranereview,preparedandmaintainedbyTheCochraneCollaborationandpublishedinTheCochraneLibrary
2011,Issue7
http://www.thecochranelibrary.com
Aromatherapyforpainmanagementinlabour(Review)
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
TABLE OF CONTENTS
HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PLAINLANGUAGESUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
AUTHORS’CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
CHARACTERISTICSOFSTUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
DATAANDANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Analysis1.2.Comparison1Aromatherapyversusstandardcare,Outcome2Assistedvaginalbirth. . . . . . . . 21
Analysis1.3.Comparison1Aromatherapyversusstandardcare,Outcome3Caesareandelivery. . . . . . . . . 21
Analysis1.4.Comparison1Aromatherapyversusstandardcare,Outcome4AdmissiontoNICU. . . . . . . . 22
Analysis1.5.Comparison1Aromatherapyversusstandardcare,Outcome5Useofpharmacologicalanalgesia. . . 22
Analysis1.6.Comparison1Aromatherapyversusstandardcare,Outcome6Spontaneousvaginaldelivery. . . . . 23
Analysis1.7.Comparison1Aromatherapyversusstandardcare,Outcome7Augmentation. . . . . . . . . . 23
Analysis2.2.Comparison2Specificaromatherapyoilversusanotheraromatherapyoil,Outcome2Assistedvaginal
delivery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Analysis2.3.Comparison2Specificaromatherapyoilversusanotheraromatherapyoil,Outcome3Caesareandelivery. 24
Analysis2.5.Comparison2Specificaromatherapyoilversusanotheraromatherapyoil,Outcome5AdmissiontoNICU. 25
Analysis2.6.Comparison2Specificaromatherapyoilversusanotheraromatherapyoil,Outcome6Apgarscore<7at5
minutes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Analysis2.7.Comparison2Specificaromatherapyoilversusanotheraromatherapyoil,Outcome7Useofpharmacological
analgesia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Analysis2.8.Comparison2Specificaromatherapyoilversusanotheraromatherapyoil,Outcome8Spontaneousvaginal
delivery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
WHAT’SNEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
CONTRIBUTIONSOFAUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
DECLARATIONSOFINTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
SOURCESOFSUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
DIFFERENCESBETWEENPROTOCOLANDREVIEW . . . . . . . . . . . . . . . . . . . . . 29
NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
INDEXTERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Aromatherapyforpainmanagementinlabour(Review) i
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
[InterventionReview]
Aromatherapy for pain management in labour
CarolineASmith1,CarmelTCollins2,CarolineACrowther3
1CentreforComplementaryMedicineResearch,UniversityofWesternSydney,PenrithSouthDC,Australia.2ChildNutritionResearch
Centre,Women’sandChildren’sHealthResearchInstitute,FlindersMedicalCentreandWomen’sandChildren’sHospital;Discipline
ofPaediatrics,TheUniversityofAdelaide,BedfordPark,Australia.3ARCH:AustralianResearchCentreforHealthofWomenand
Babies,DisciplineofObstetricsandGynaecology,TheUniversityofAdelaide,Adelaide,Australia
Contactaddress:CarolineASmith,CentreforComplementaryMedicineResearch,UniversityofWesternSydney,LockedBag1797,
PenrithSouthDC,NewSouthWales,2751,[email protected].
Editorialgroup:CochranePregnancyandChildbirthGroup.
Publicationstatusanddate:Edited(nochangetoconclusions),publishedinIssue8,2011.
Reviewcontentassessedasup-to-date: 28April2011.
Citation: SmithCA,CollinsCT,CrowtherCA.Aromatherapyforpainmanagementinlabour.CochraneDatabaseofSystematicReviews
2011,Issue7.Art.No.:CD009215.DOI:10.1002/14651858.CD009215.
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
ABSTRACT
Background
Manywomenwouldliketoavoidpharmacologicalorinvasivemethodsofpainmanagementinlabourandthismaycontributetowards
thepopularityofcomplementarymethodsofpainmanagement.Thisreviewexaminedcurrentlyavailableevidencesupportingtheuse
ofaromatherapyforpainmanagementinlabour.
Objectives
Toexaminetheeffectsofaromatherapyforpainmanagementinlabouronmaternalandperinatalmorbidity.
Searchmethods
We searchedthe Cochrane Pregnancy and Childbirth Group’s Trials Register (31 October 2010), The Cochrane Complementary
MedicineField’sTrialsRegister(October2010),theCochraneCentralRegisterofControlledTrials(TheCochraneLibrary2010,Issue
4),MEDLINE(1966to31October2010),CINAHL(1980to31October2010),theAustralianandNewZealandTrialsRegistry(31
October2010),ChineseClinicalTrialRegister(31October2010),CurrentControlledTrials(31October2010),ClinicalTrials.gov
(31October2010),ISRCTNRegister(31October2010),NationalCenterforComplementaryandAlternativeMedicine(NCCAM)
(31October2010)andtheWHOInternationalClinicalTrialsRegistryPlatform(31October2010).
Selectioncriteria
Randomisedcontrolledtrialscomparingaromatherapywithplacebo,notreatmentorothernon-pharmacologicalformsofpainman-
agementinlabour.
Datacollectionandanalysis
Twoauthorsindependentlyassessedtrialqualityandextracteddata.Wecontactedstudyauthorsforadditionalinformation.
Aromatherapyforpainmanagementinlabour(Review) 1
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Mainresults
Weincludedtwotrials(535women)inthereview.Thetrialsfoundnodifferencebetweengroupsfortheprimaryoutcomesofpain
intensity,assistedvaginalbirth(riskratio(RR)1.04,95%confidenceinterval(CI)0.48to2.28,onetrial,513women;RR0.83,95%
CI0.06to11.70,onetrial,22women),andcaesareansection(RR0.98,95%CI0.49to1.94,onetrial,513women;RR2.54,95%
CI0.11to56.25,onetrial,22women);thereweremorebabiesadmittedtoneonatalintensivecareinthecontrolgroupofonetrial
(RR0.08,95%CI0.00to1.42,onetrial,513women)butthisdifferencedidnotreachstatisticalsignificance.Thetrialsfoundno
differencesbetweengroupsforthesecondaryoutcomesofuseofpharmacologicalpainrelief(RR0.35,95%CI0.04to3.32,onetrial,
513women;RR2.50,95%CI0.31to20.45,onetrial,22women),spontaneousvaginaldelivery(RR1.00,95%CI0.94to1.06,
onetrial,513women;RR0.93,95%CI0.67to1.28,onetrial,22women)orlengthoflabourandaugmentation(RR1.14,95%CI
0.90to1.45,onetrial,513women).Theriskofbiaswaslowinthetrials.
Authors’conclusions
There is a lack of studies evaluating the role of aromatherapy for pain management in labour. Further research is needed before
recommendationscanbemadeforclinicalpractice.
PLAIN LANGUAGE SUMMARY
Aromatherapyforpainmanagementinlabour
Aromatherapydrawsonthehealingpowerofplantswiththeuseofessentialoilstoenhancephysicalandmentalwellbeing.Theoilsmay
bemassagedintotheskin,inabathorinhaledusingasteaminfusionorburner.Thepainoflabourcanbeintense,withtension,fearand
anxietymakingitworse.Manywomenwouldliketolabourwithoutusingdrugs,orinvasivemethodssuchasanepidural,andturnto
complementarytherapiestohelpreducetheirpainperceptionManycomplementarytherapiesaretriedandincludeacupuncture,mind-
bodytechniques,massage,reflexology,herbalmedicinesorhomoeopathy,hypnosis,musicandaromatherapy.Thereviewidentified
tworandomisedcontrolledtrialsofaromatherapy.Onetrialinvolving513womencomparedoneofRomanchamomile,clarysage,
frankincense,lavenderormandarinessentialsoilswithstandardcare.Thearomatherapywasappliedusingacupressurepoints,taper,
compress,footbath,massageorabirthingpool.Thesecondtrialinvolved22womenrandomisedtobatheforatleastanhourinwater
witheitheressentialoilofgingerorlemongrassadded.Allwomenreceivedroutinecareandhadaccesstopainrelief.Thetrialsfoundno
differencebetweengroupsforpainintensity,assistedvaginalbirth,caesareansectionortheuseofpharmacologicalpainrelief(epidural).
Overall,thereisinsufficientevidencefromrandomisedcontrolledtrialsaboutthebenefitsofaromatherapyonpainmanagementin
labour.Moreresearchisneeded.
BACKGROUND beendescribedasoneofthemostintenseformsofpainthatcan
be experienced(Melzack 1984).Pain experiencedby women in
ThisreviewisoneinaseriesofCochranereviewsexaminingpain
labouriscausedbyuterinecontractions,thedilatationofthecervix
managementinlabour.Thesereviewscontributetoanoverview
and,inthelatefirststageandsecondstage,thestretchingofthe
ofsystematicreviewsofpainmanagementforwomeninlabour
vaginaandpelvicfloortoaccommodatethebaby.Tension,anxiety
(Neilson2011b),andshareagenericprotocol(Neilson2011a).
andfeararefactorscontributing towardswomen’sperceptionof
pain and may also affect their labour and birth experience.The
neuromatrix theory of pain understands the influence of many
Descriptionofthecondition factorsincludingpastexperienceandmemory(Melzack2001).In
labourthetheoryofpainincorporateselementsofthegatecontrol
Labour presents a physiological and psychological challenge for
theory,butalsopastexperiences,culturalfactors,emotionalstate,
women. As labour becomes more imminent this can be a time
cognitiveinput,stressregulationandimmunesystems,aswellas
of conflicting emotions; fear and apprehension can be coupled
immediatesensoryinput(Trout2004).Effectiveandsatisfactory
with excitement andhappiness. Pain associated with labour has
Aromatherapyforpainmanagementinlabour(Review) 2
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
painmanagementneedstobeindividualisedforeachwoman,and The most commonly cited complementary medicine and prac-
maybeinfluencedbytwoparadigms:workingwithpain,orpain tices associated with providing pain management in labour can
relief(Leap1997).Theworkingwithpainparadigmincludesthe becategorisedintomind-bodyinterventions(e.g.yoga,hypnosis,
beliefthattherearelong-termbenefitstopromotingnormalbirth, relaxationtherapies),wholemedicalsystems(e.g.homoeopathy,
andthatpainplaysanimportantroleinthisprocess.Theworking traditionalChinesemedicine),manualhealingmethods(e.g.mas-
withpainapproachofferssupportandencouragementtowomen, sage,reflexology),pharmacologicandbiologicaltreatments,bio-
advocates the use of immersion in water, comfortable positions electromagneticapplications(e.g.magnets)andherbalmedicines.
and self-helptechniques to cope with normal labour pain. The Aromatherapy involves the use of the essential oils, which are
painreliefparadigmischaracterisedbythebeliefthatnowoman volatile,fragrantorganiccompoundsobtainedbydistillationfor
need suffer pain in labour and women are offered a variety of plantmaterialderivedfromroots,leaves,bark,seedsandflowers.
pharmacologicalpainrelief. Theessentialoilsareusuallymixedwithacarrieroil.Thesearevir-
ginorcold-pressedandtheclinicalpresentationismatchedwith
thecarrieroil.All-purposecarrieroilsincludegrapeseed,sweetal-
mondandsesame.Othercarrieroilsincludeherbaloilsthatcon-
Descriptionoftheintervention tainactiveingredientsincludingcalendula,arnica,sheabutteror
aloevera.Themechanismofactionforaromatherapyisunclear.
The use of complementary therapies and medicines (CM) has
Studiesinvestigatingpsychologicalandphysiologicaleffectsofes-
becomepopularwithconsumersworldwide.Studiessuggestthat
sentialoilsshowednochangeonphysiologicalparameterssuchas
between36%and62%ofadultsfromindustrialisednationsuse
blood pressure or heartrate,but didproduce psychological im-
some form of CM to prevent or treat health-related problems
provementinmoodandanxietylevels(Stevensen1995).Essential
(Barnes 2004). Complementary therapies are more commonly
oilsarethoughttoincreasetheoutputofthebody’sownsedative,
usedbywomenofreproductiveage,withalmosthalf(49%)re-
stimulantandrelaxingsubstances.Theoilsmaybemassagedinto
portinguse(Eisenberg1998).Itispossiblethatasignificantpro-
the skin, or inhaled by using a steam infusion or burner. Aro-
portionofwomenusethesetherapiesduringpregnancy.Arecent
matherapyisincreasinginpopularityamongmidwivesandnurses
reviewoftheuseofCMinpregnancyidentifiedaprevalencerate
(Allaire2000).Themostcommon application of aromatherapy
from 14 studies with large sample sizes (n > 200) ranged from
duringlabourisbymassage,bathorinhalation,andtwooilscom-
1%to87% (with nine fallingbetween20% and 60%)(Adams
monly used include lavender and frankincense (Simkin 2004).
2009).Thereviewidentifieduseofvariouscomplementaryther-
Otheressentialoilsusedduringlabouranddeliveryincludeeuca-
apiesincludingacupuncture/acupressure,aromatherapy,massage,
lyptus,jasmine,romanchamomile(pain),clarysage(increasecon-
yoga,homeopathyandchiropracticcare.Themostfrequentlyused
tractions),lemon(elevatedmood),mandarin,nerdi,ylangylang
herbalmedicinesduringpregnancywereginger,raspberryleafand
(relaxation)androse(anxiety)(Burns1999;Tiran2000).
echinacea.Evidencealsoshowedthatmanypregnantwomenhad
Therehavebeennostudiesorpublishedanecdotalevidencethat
used more thanone complementary product or service (Adams
demonstrate harmfromessentialoilstomotheror fetus(Tillett
2009).Manywomenwouldliketoavoidpharmacologicalorin-
2010), although a review of the use of essential oils in 8058
vasive methodsof pain reliefin labour andthismay contribute
womenfound1%hadamildunpleasantresponsetooilsinclud-
towardsthepopularityofcomplementarymethodsofpainman-
ingrose,jasmine,chamomile,eucalyptus,lemon,mandarin,clary
agement(Bennett1999).
sage, frankincense, lavenderandpeppermint;noresponseswere
TheComplementaryMedicineFieldoftheCochraneCollabora-
harmfultothewomanorthefetus(Burns2000).Essentialoilsare
tiondefinescomplementarymedicineas’practicesandideaswhich
concentratedsubstancesandinsomecasescancauseskinirrita-
areoutsidethedomainofconventionalmedicineinseveralcoun-
tions;conductingapatchtestontheskincancheckforallergies
tries’,whicharedefinedbyitsusersas’preventingortreatingill-
(Tillett2010).
ness,orpromotinghealthandwellbeing’(Manheimer2008).This
definition is deliberatelybroad, astherapiesconsidered comple-
mentarypracticesinonecountryorculturemaybeconventional
inanother.Manytherapiesandpracticesareincludedwithinthe
scopeoftheComplementaryMedicineField.Theseincludetreat- OBJECTIVES
ments people can administer themselves (e.g. botanicals, nutri-
tionalsupplements,healthfood,meditation,magnetictherapy), Toexaminetheeffectsofaromatherapyforpainmanagementin
treatments providers administer (e.g. acupuncture, massage, re- labouronmaternalandperinatalmorbidity.
flexology,chiropracticandosteopathicmanipulations),andtreat-
Thisreviewexaminesthehypothesesthattheuseofaromatherapy
mentspeoplecanadministerundertheperiodicsupervisionofa
is:
provider(e.g.yoga,biofeedback,TaiChi,homoeopathy,Alexan-
dertherapy,Ayurveda).
Aromatherapyforpainmanagementinlabour(Review) 3
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
1. aneffectivemeansofpainmanagementinlabouras 11. Inhaledanalgesia
measuredbydecreasesinwomen’sratingoflabourpain:a 12. Opioids(Ullman2010)
reducedneedforpharmacologicalintervention; 13. Non-opioiddrugs(Othman2011)
14. Localanaestheticnerveblocks
2. improvedmaternalsatisfactionormaternalemotional
15. Epidural(includingcombinedspinalepidural)
experience;and
(Anim-Somuah2005;Simmons2007)
3. aromatherapyhasnoadverseeffectsonthemother Accordingly,thisreviewincludescomparisonsofoneformofaro-
(durationoflabour,modeofdeliver)orbaby. matherapy compared with any other form of aromatherapy, or
aromatherapy compared with: 1. placebo/no treatment; 2. hyp-
nosis;3.biofeedback;4.sterilewaterinjection;or5.immersion
METHODS inwater.
Typesofoutcomemeasures
Criteriaforconsideringstudiesforthisreview
ThisreviewisoneinaseriesofCochranereviewsexaminingpain
managementinlabour.Thesereviewscontributetoanoverviewof
systematicreviewsofinterventionsforpainmanagementinlabour
Typesofstudies
(Neilson2011b),andshareagenericprotocol(Neilson2011a).
Randomised controlled trials (RCTs) only. (We do not plan to The following list of primary outcomes are the ones which are
include resultsfromquasi-RCTs in the analyses but we may be commontoallthereviews.
discusstheminthetextiflittleotherevidenceisavailable.)
Primaryoutcomes
Typesofparticipants
Womeninlabour. (Thisincludeswomeninhigh-riskgroups,e.g.
pretermlabourorfollowinginductionoflabour.Weplannedto Effectsofinterventions
usesubgroupanalysisforanypossibledifferencesintheeffectof • Painintensity(asdefinedbytrialists)
interventionsinthesegroups.) • Satisfactionwithpainrelief
• Senseofcontrolinlabour(asdefinedbytrialists)
• Satisfactionwithchildbirthexperience
Typesofinterventions
ThisreviewisoneinaseriesofCochranereviewsexaminingpain
managementinlabour.Thesereviewscontributetoanoverviewof Safetyofinterventions
systematicreviewsofinterventionsforpainmanagementinlabour • Effect(negative)onmother/babyinteraction
(Neilson2011b),andshareagenericprotocol(Neilson2011a). • Breastfeeding(atspecifiedtimepoints)
Toavoidduplication,thedifferentmethodsofpainmanagement • Assistedvaginalbirth
have been listed in a specific order, from one to 15. Individual • Caesareansection
reviewsfocusingonparticularinterventionsincludecomparisons • Sideeffects(formotherandbaby;reviewspecific)
withonlytheinterventionaboveitonthelist.Methodsofpain • Admissiontospecialcarebabyunit/neonatalintensivecare
managementidentifiedinthefuturewillbeaddedtotheendof unit(asdefinedbytrialists)
thelist.Thecurrentlistisasfollows. • Apgarscorelessthansevenatfiveminutes
1. Placebo/notreatment • Poorinfantoutcomesatlong-termfollow-up(trialist
2. Hypnosis defined)
3. Biofeedback(Barragán2006)
4. Intracutaneousorsubcutaneoussterilewaterinjection
(Derry2011) Otheroutcomes
5. Immersioninwater(Cluett2009) • Cost(asdefinedbytrialists)
6. Aromatherapy(thisreview)
7. Relaxationtechniques(yoga,music,audio)
8. Acupunctureoracupressure(Smith2011) Secondaryoutcomes
9. Manualmethods(massage,reflexology)
10. Transcutaneouselectricalnervestimulation(TENS)
(Dowswell2009) Maternal
Aromatherapyforpainmanagementinlabour(Review) 4
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Useofpharmacologicalpainreliefinlabour;spontaneousvaginal and the WHO International Clinical Trials Registry Platform (
delivery;lengthoflabour;needforaugmentationwithoxytocin; ICTRP)(Appendix4).
perinealtrauma(definedasepisiotomyandincidenceofsecond- Wedidnotapplyanylanguagerestrictions.
orthird-degreetear);andmaternalbloodloss(postpartumhaem-
orrhagedefinedasgreaterthan600ml).
Datacollectionandanalysis
Weusedthefollowingmethodswhenassessingthereportsiden-
Neonatal
tifiedbythesearch.
Needformechanicalventilation;neonatalencephalopathy.
Selectionofstudies
Searchmethodsforidentificationofstudies CSmith(CS)andCTCollins(CTC)screenedthetitlesandab-
stractsofarticlesfoundinthesearch,anddiscardedtrialsthatwere
clearlynoteligible.Twooutofthethreereviewauthors(CS,CTC,
CACrowther(CAC))undertooktrialselection.
Electronicsearches
CSandCTCindependently assessedwhetherthetrialsmetthe
WesearchedtheCochranePregnancyandChildbirthGroup’sTri- inclusioncriteria,withdisagreementsresolvedbydiscussionwith
alsRegisterbycontactingtheTrialsSearchCo-ordinator(31Oc- thethirdauthor(CAC).Whenarticlescontainedinsufficientin-
tober2010). formationtomakeadecisionabouteligibility,CSattemptedto
TheCochranePregnancyandChildbirthGroup’sTrialsRegister contactauthorsoftheoriginalreportstoobtainfurtherdetails.
ismaintainedbytheTrialsSearchCo-ordinatorandcontainstrials
identifiedfrom:
1. quarterlysearchesoftheCochraneCentralRegisterof Dataextractionandmanagement
ControlledTrials(CENTRAL); Following an assessment for inclusion, CS and CTC indepen-
2. weeklysearchesofMEDLINE; dentlyextracteddatausingtheformdesignedbytheReviewGroup
3. weeklysearchesofEMBASE; forthispurpose.Foreligiblestudies,tworeviewauthorsextracted
4. handsearchesof30journalsandtheproceedingsofmajor data using the agreed form. We resolved discrepancies through
conferences; discussion or,ifrequired,weconsultedathirdperson.Foreach
5. weeklycurrentawarenessalertsforafurther44journals includedtrial,wecollectedinformationregardingthelocationof
plusmonthlyBioMedCentralemailalerts. thetrial,methodsofthetrial(asperassessmentofriskofbias),
DetailsofthesearchstrategiesforCENTRALandMEDLINE, theparticipants(agerange,eligibilitycriteria),thenatureofthe
thelistofhandsearchedjournalsandconferenceproceedings,and interventions,anddatarelatingtotheoutcomesspecifiedabove.
thelistofjournalsreviewedviathecurrentawarenessservicecan Wecollectedinformationonreportedbenefitsandadverseeffects.
be found in the ‘Specialized Register’ section within the edito- When information regarding any of the above was unclear, we
rialinformation about the CochranePregnancyandChildbirth attempted to contact authors of the original reports to provide
Group. further details. We entered data into Review Manager software
Trialsidentifiedthroughthesearchingactivitiesdescribedabove (RevMan2011)andcheckedforaccuracy.
areeachassignedtoareviewtopic(ortopics).TheTrialsSearch
Co-ordinatorsearchestheregisterforeachreviewusingthetopic
Assessmentofriskofbiasinincludedstudies
listratherthankeywords.
WesearchedtheCochraneComplementaryMedicineField’sTrials Two review authors independently assessed the risk of bias for
Registerusingtheterms(laborORlabour)(October2010). eachstudyusingthecriteriaoutlinedintheCochraneHandbook
Inaddition,wesearchedtheCochraneCentralRegisterofCon- forSystematicReviewsofInterventions(Higgins2011).Weresolved
trolledTrials(TheCochraneLibrary2010,Issue4)(Appendix1), anydisagreementbydiscussionorbyinvolvingathirdassessor.
MEDLINE(1966to31October2010)(Appendix2),CINAHL Thetoolconsistsofsixitems.Therearethreepotentialresponses:
(1980to31October2010)(Appendix3). highrisk,lowriskorunclearrisk.Wealsomadeajudgementof
Wealsosearchedthefollowingclinicaltrialregistriesandwebsites ‘unclear’ifwhathappenedinthestudywasknownbuttheriskof
forongoingtrialson31October2011: biaswasunknown;orifanentrywasnotrelevanttothestudyat
AustralianandNew hand(particularlyforassessingblindingandincompleteoutcome
ZealandTrialsRegistry;ChineseClinicalTrialRegister;Current data, or when the outcome being assessed by the entry has not
ControlledTrials;ClinicalTrials.gov;ISRCTNRegister;National beenmeasuredinthestudy).
CenterforComplementaryandAlternativeMedicine(NCCAM);
Aromatherapyforpainmanagementinlabour(Review) 5
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Weassessedthefollowingcharacteristics:sequencegeneration,al- Wheresufficientinformationwasreported,orcouldbesupplied
locationconcealment,blinding(ormasking),incompletedataas- bythetrialauthors,were-includedmissingdataintheanalyses
sessment,selectiveoutcomereporting,othersourcesofbias,de- whichweundertook.
scribed below. We generateda’riskof bias assessment’ table for Weassessedmethodsas:
eachstudy. • lowriskofbias(e.g.nomissingoutcomedata;missing
outcomedatabalancedacrossgroups);
• highriskofbias(e.g.numbersorreasonsformissingdata
(1)Randomsequencegeneration(checkingforpossible
imbalancedacrossgroups;‘astreated”analysisdonewith
selectionbias)
substantialdepartureofinterventionreceivedfromthatassigned
Wedescribedforeachincludedstudythemethodusedtogenerate atrandomisation)
theallocationsequenceinsufficientdetailtoallowanassessment • unclearriskofbias.
ofwhetheritshouldproducecomparablegroups.
Wewillassessedthemethodas:
• lowriskofbias(anytrulyrandomprocess,e.g.random (5)Selectivereporting(checkingforreportingbias)
numbertable;computerrandomnumbergenerator),
We described for each included study how we investigated the
• highriskofbias(anynon-randomprocess,e.g.oddoreven
possibilityofselectiveoutcomereportingbiasandwhatwefound.
dateofbirth;hospitalorclinicrecordnumber)or,
Weassessedthemethodsas:
• unclearriskofbias.
• lowriskofbias(whereitisclearthatallofthestudy’spre-
specifiedoutcomesandallexpectedoutcomesofinteresttothe
(2)Allocationconcealment(checkingforpossibleselection reviewhavebeenreported);
bias) • highriskofbias(wherenotallthestudy’spre-specified
outcomeshavebeenreported;oneormorereportedprimary
We described for each included study the methodused tocon-
outcomeswerenotpre-specified;outcomesofinterestare
cealallocationtointerventionspriortoassignmentandassessed
reportedincompletelyandsocannotbeused;studyfailsto
whetherintervention allocationcouldhavebeenforeseeninad-
includeresultsofakeyoutcomethatwouldhavebeenexpected
vanceof,orduringrecruitment,orchangedafterassignment.
tohavebeenreported);
Weassessedthemethodsas:
• lowriskofbias(e.g.telephoneorcentralrandomisation; • unclearriskofbias.
consecutivelynumberedsealedopaqueenvelopes);
• highriskofbias(openrandomallocation;unsealedornon-
(6)Otherbias(checkingforbiasduetoproblemsnot
opaqueenvelopes,alternation;dateofbirth);
• unclearriskofbias. coveredby1to5above)
Wedescribedforeachincludedstudyanyimportantconcernswe
hadaboutotherpossiblesourcesofbias.
(3)Blinding(checkingforpossibleperformancebias)
Weassessedwhethereachstudywasfreeofotherproblemsthat
Wejudgedthatblindingofparticipantsandcaregiverwouldnot couldputitatriskofbias:
bepossibleduetothetypeofinterventionbeingassessed.Forthis • lowriskofotherbias;
reasonweassessedwhetherthelackofblindingwaslikelytohave • highriskofotherbias;
introducedbiasinthemeasureofoutcomesofinterest.Blinding • unclearwhetherthereisriskofotherbias.
wasassessedforprimaryoutcomesas:
• low,highorunclearriskofbias.
(7)Overallriskofbias
(4)Incompleteoutcomedata(checkingforpossibleattrition Wemadeexplicitjudgementsaboutwhetherstudiesareathighrisk
biasduetotheamount,natureandhandlingofincomplete ofbias,accordingtothecriteriagivenintheHandbook(Higgins
outcomedata) 2011).Withreferenceto(1)to(6)above,weassessedthelikely
magnitude anddirectionofthebiasandwhetherweconsidered
Wedescribedforeachincludedstudy, andforeachoutcome or
it likely to impact on the findings. We planned to explore the
classofoutcomes,thecompletenessofdataincludingattritionand
impactofthelevelofbiasthroughundertakingsensitivityanalyses
exclusionsfromtheanalysis.Westatedwhetherattritionandex-
-see’Sensitivityanalysis’.
clusionswerereportedandthenumbersincludedintheanalysisat
eachstage(comparedwiththetotalrandomisedparticipants),rea-
sonsforattritionorexclusionwherereported,andwhethermiss-
Measuresoftreatmenteffect
ingdatawerebalancedacrossgroupsorwererelatedtooutcomes.
Aromatherapyforpainmanagementinlabour(Review) 6
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
Dichotomousdata Assessmentofheterogeneity
Fordichotomousdata,wepresentedresultsassummaryriskratio We assessedstatistical heterogeneityineachmeta-analysis using
with95%confidenceintervals(CI). theT²,I²andChi²statistics.Weregardedheterogeneityassub-
stantialifT²wasgreaterthanzeroandeitherI²wasgreaterthan
50%ortherewasalowPvalue(lessthan0.10)intheChi²test
forheterogeneity.
Continuousdata
Weexpressedcontinuousdataasmeandifferenceswith95%CIs,
orasstandardisedmeandifferencesifoutcomeswereconceptually Assessmentofreportingbiases
the same in the different trials but measured in different ways. Iftherewere10ormorestudiesinthemeta-analysisweplannedto
Weexpectedtherewouldbeclinicalandstatisticalheterogeneity investigatereportingbiases(suchaspublicationbias)usingfunnel
inthetrialsincludedinthereview, andanalyseddatausing the plots.Wewouldassessfunnelplotasymmetryvisually,andwould
random-effectsmodel. useformaltestsforfunnelplotasymmetry.Forcontinuous out-
comeswewouldusethetestproposedbyEgger1997,andfordi-
chotomousoutcomeswewouldusethetestproposedbyHarbord
Unitofanalysisissues 2006.Ifwedetectedasymmetryinanyofthesetestsorbyavi-
sualassessment,weproposedtoperformexploratoryanalysesto
investigateit.
Cluster-randomisedtrials
Datasynthesis
Weaimedtoincludecluster-randomisedtrialsintheanalysesalong
WecarriedoutstatisticalanalysisusingtheReviewManagersoft-
withindividuallyrandomisedtrials.Wewouldadjusttheirsample
ware(RevMan2011).Weusedrandom--effectsmeta-analysisfor
sizesorstandarderrorsusingthemethodsdescribedintheHand-
combiningdatawhereitisreasonabletoassumethatstudieswere
bookusinganestimateoftheintraclustercorrelationco-efficient
estimatingthesameunderlyingtreatmenteffect:i.e.wheretrials
(ICC)derivedfromthetrial(ifpossible),fromasimilartrialor
wereexaminingthesameintervention,andthetrials’populations
fromastudyofasimilarpopulation.IfweuseICCsfromother
andmethodswerejudgedsufficientlysimilar.Iftherewasclinical
sources,weplannedtoreportthisandconductsensitivityanalyses
heterogeneitysufficienttoexpectthattheunderlyingtreatmentef-
toinvestigate the effectof variation in theICC. We considered
fectsdifferedbetweentrials,orifwedetectedsubstantialstatistical
itreasonabletocombinetheresultsfrombothiftherewaslittle
heterogeneity,weusedarandom-effectsmeta-analysistoproduce
heterogeneitybetweenthestudydesignsandtheinteractionbe-
anoverallsummaryifanaveragetreatmenteffectacrosstrialswas
tweentheeffectofinterventionandthechoiceofrandomisation
consideredclinicallymeaningful. Wetreatedtherandom-effects
unitwasconsideredtobeunlikely.Wewouldalsoacknowledge
summaryastheaveragerangeofpossibletreatmenteffectsandwe
heterogeneityintherandomisationunitandperformasensitivity
planned to discuss the clinical implications of treatment effects
orsubgroupanalysistoinvestigatetheeffectsoftherandomisation
differing between trials. If the average treatment effect was not
unit.
clinicallymeaningfulwehavenotcombinedtrials.
If we used the random-effects analyses, we have presented the
resultsastheaverage treatmenteffectwith its95% CI,and the
Dealingwithmissingdata
estimatesof T²andI².
For included studies, we noted levelsof attrition. We aimed to
exploretheimpactofincludingstudieswithhighlevelsofmissing
Subgroupanalysisandinvestigationofheterogeneity
dataintheoverallassessmentoftreatmenteffectbyusingsensi-
tivityanalysis. Ifwehadidentifiedsubstantialheterogeneity,wewouldhavein-
For all outcomes, we carried out analyses, as far as possible, on vestigateditusingsubgroupanalysisandsensitivityanalyses.We
anintention-to-treatbasis,i.e.weattemptedtoincludeallpartic- wouldconsiderwhetheranoverallsummarywasmeaningful,and
ipantsrandomisedtoeachgroupintheanalyses,andallpartici- ifitis,userandom-effectsanalysistoproduceit.
pantswereanalysedinthegrouptowhichtheywereallocated,re- Weplannedtocarryoutthefollowingsubgroupanalyses.
gardlessofwhetherornottheyreceivedtheallocatedintervention. 1. Spontaneouslabourversusinducedlabour.
Thedenominatorforeachoutcomeineachtrialwasthenumber 2. Primiparousversusmultiparous.
randomised minus any participants whose outcomes are known 3. Termversuspretermbirth.
tobemissing.Weexcludedtrialswithgreaterthan20%missing 4. Continuoussupportinlabourversusnocontinuous
datafromtheanalysis. support.
Aromatherapyforpainmanagementinlabour(Review) 7
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.
For random-effects inverse variance meta-analyses, we aimed to Studylocationandsourcesofwomen
assessdifferencesbetweensubgroupsbyinteractiontests.Forran-
Burns2007recruitedwomenfromdeliverysuiteinItaly.Calvert
dom-effectsmeta-analysesusingmethodsotherthaninversevari-
2000 recruitedwomenduringtheantenatalperiod,atalevelII
ance,we wouldassessdifferencesbetweensubgroups byinspec-
hospitalinNewZealand.
tionofthesubgroups’confidenceintervals;non-overlappingcon-
fidence intervals indicate a statistically significant difference in
treatmenteffectbetweenthesubgroups.
Participants
Nulliparousandmultiparouswomenwithasingletonpregnancy.
Sensitivityanalysis
Wheresubgroup analysisfailedtoexplaintheheterogeneity,we
wouldanalysedatausingtherandom-effectsmodel.Apriori,we Intervention
plannedtoperformsensitivity analysesonresultstolookatthe IntheBurns 2007 trialthedecision astowhichessential oilto
possiblecontributionof:(1)differencesinmethodologicalquality, use, together with mode(s) of application was reached through
withtrialsofhighquality(lowriskofbias)comparedtoalltrials; discussionbetweenthemidwifeandwoman.Theycoulduseone
and(2)publicationbiasbycountry.Ifpublicationbiaswaspresent, of five essential oils (EOs): Roman chamomile (Chamaemelum
weplannedtoundertakeasensitivityanalysisexcludingtrialsfrom nobile),clarysage(Salviasclarea),frankincense(Boswelliacarteri),
countrieswheretherewasagreaterpublicationbias. lavender(Lavandulaaugustifolium) andmandarin(Citrusretic-
ulata).Aromatherapywasadministeredforoneofthefollowing
reasons:toreducefear,reduceanxiety,alleviatepainortoaugment
contractions. Modesofapplication includedacupressure points,
RESULTS taper,compress,footbath,massageorbirthingpool.Eachwoman
assignedaromatherapyreceivedoneEO(noblending).
In the Calvert 2000 study women were randomised to receive
essential oil of ginger or essential oil of lemongrass in thebath.
Descriptionofstudies
Womenwererequiredtobatheforatleastonehour.Allwomen
See:Characteristicsofincludedstudies;Characteristicsofstudies receivedroutinecareandhadaccesstopainrelief.
awaitingclassification;Characteristicsofongoingstudies.
Outcomes
Resultsofthesearch
Thetrialsreportedonpainintensity, assistedvaginal birth,cae-
The original review included a range of complementary thera-
sareansection,sideeffectsfromessentialoils,admissiontoneona-
pies (Smith 2006). This updated review includes aromatherapy
tal intensive care unit, Apgar scores, use of pharmacological
trials only; we included two trials (Burns 2007, 513 women;
painrelief,spontaneousvaginaldelivery,augmentation, perineal
Calvert 2000, 22 women), and excluded no trials. We identi-
trauma, length of first and second stage of labour, frequency of
fied two additional new trials (Hur 2003; Salem 2004) which
contractions,cervicaldilatationanddirectrooming-in.
are awaiting further assessment. See Characteristics of included
studies, Characteristics of studies awaiting classification, and
Characteristicsofongoingstudies.
Baselinecomparability
BaselinecharacteristicsweresimilarintheBurns2007trial.Data
Includedstudies onbaselinecomparabilitywerenotreportedintheCalvert2000
study.
Studydesign
Bothstudiesusedaparalleldesignwithtwostudygroups.Burns Intentiontotreat
2007usedstandardcareasacontrolgroup.Calvert2000usedan
Anintention-to-treatanalysiswasreported.
activecontroloflemongrass.
Sourceoffunding
SampleSize
Samplesizerangedfrom22(Calvert2000)to513(Burns2007) AuniversitygrantfundedtheBurns2007trial.Nofundingwas
participants. reportedintheCalvert2000.
Aromatherapyforpainmanagementinlabour(Review) 8
Copyright©2011TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.