Full length article
Insomnia before and after childbirth: The risk of developing postpartum pain — A longitudinal population-based study
$Børge Sivertsen
a,b,c,*, Keith J. Petrie
d, Jens Christoffer Skogen
a,b,e, Mari Hysing
b, Malin Eberhard-Gran
a,f,gaDomainforMentalandPhysicalHealth,NorwegianInstituteofPublicHealth,P.O.Box973Sentrum,5808Bergen,Norway
bTheRegionalCentreforChildandYouthMentalHealthandChildWelfare,UniResearchHealth,Bergen,P.O.Box7810,N-5020Bergen,Norway
cDepartmentofPsychiatry,HelseFonnaHF,P.O.Box2170,N-5504Haugesund,Norway
dDepartmentofPsychologicalMedicine,UniversityofAuckland,Auckland1142,NewZealand
eAlcoholandDrugResearchWesternNorway,StavangerUniversityHospital,Stavanger,Norway
fHealthServicesResearchCenter,AkershusUniversityHospital,Lørenskog,Norway
gInstituteofClinicalMedicine,CampusAhus,UniversityofOslo,Lørenskog,Norway
ARTICLE INFO
Articlehistory:
Received28October2016 Accepted16January2017 Availableonlinexxx
Keywords:
Sleep Pain Longitudinal Epidemiology Pregnancy
ABSTRACT
Objective:Toexamineifinsomniabeforeandafterchildbirthpredictsthedevelopmentofpostpartum bodilypain.
Methods:Thisstudyispartofalongitudinalcohortstudy,theAkershusBirthCohortStudy, which targetedall womengivingbirthatAkershusUniversityHospitalinNorway. Thecurrentsampleis comprisedof1480womenwhoparticipatedatallthreetimepoints,yieldingaparticipationrateof32%of the4662womenwhooriginallyconsentedtoparticipate.TheBergenInsomniaScale(BIS)wasusedto measureinsomniaandalatentprofileanalysis(LPA)wasusedtoidentifysubsetsofwomenwhoshareda similarpatternofresponsesontheBIS-scaleacrossthethreetimepoints.Painwasmeasuredusingthe bodily painscale,derivedfrom thePrimaryCare Evaluationof Mental Disorders(PRIME-MD)and symptomsofdepressionweremeasuredbytheEdinburghPostnatalDepressionScale(EPDS).
Results:Usingalatentprofileanalysisathreeclassmodelshowedthebestfitandidentifiedonemajor group(55.6%)withalowBISscoresacrossallthreetimepoints,onegroupwithintermediateBISscores (32.9%),andasmallergroup(11.5%)withhigherBISscoresacrossallthreetimes.Thechronichigh insomniagroup had a 2.8-fold increasedrisk of reporting highlevels of bodily pain. Thechronic intermediategroupwasassociatedwitha2.2-foldincreasedriskofbodilypainattwoyearspostpartum.
Adjustingfordemographicsandlifestylebehaviorsdidnotreduceanyoftheassociations,whileadjusting fordepressionsignificantlyattenuatedtheassociations.Additionaladjustmentforpainateightweeks postpartumfurtherreducedthemagnitudeoftheassociations,butbothchronicintermediateinsomnia andchronichighinsomniaremainedstronglyassociatedwiththeonsetofbodilypaininthefully adjustedmodels(RR=1.75,95%CI:1.37–2.23)andRR=1.63,95%CI:1.15–2.32,respectively).
Conclusions:Thehighprevalenceofinsomniaamongwomenduringandafterchildbirth,incombination withthestrongprospectiveassociationwithimpairedphysicalhealth,emphasizestheimportanceof adequatelyidentifying,preventingandtreatinginsomniaforthispopulation.
©2017ElsevierB.V.Allrightsreserved.
Introduction
Insomnia is a rising public health concern, and it is now estimated that around 15% of the adult population fulfills the
diagnosticcriteria foran insomniadisorder[1,2], asdefined by difficultyinitiatingormaintainingsleep,foratleast3months,in combination withimpaired daytime functioning caused by the sleepdisturbance[3]. Womenreportinsomniamorefrequently thanmen[4],andthissex-specificpatterntendstoemergeinlate adolescence[5].Pregnancyand thepostnatal periodmaybean especiallyvulnerableperiodfordevelopinginsomniainwomen.In a previouspublication we found a very high prevalence of an insomniadisorder(approximately60%)bothbeforeandimmedi- ately after childbirth and although the prevalence decreased
$Condensation:Chronicinsomniaduringandafterpregnancyisariskfactorfor lateronsetofbodilypain.
*Correspondingauthorat:DomainforMentalandPhysicalHealth,Norwegian InstituteofPublicHealth,P.O.Box973Sentrum,5808Bergen,Norway.
E-mailaddresses:borge.sivertsen@fhi.no,borge.sivertsen@uni.no(B.Sivertsen).
http://dx.doi.org/10.1016/j.ejogrb.2017.01.020 0301-2115/©2017ElsevierB.V.Allrightsreserved.
ContentslistsavailableatScienceDirect
European Journal of Obstetrics & Gynecology and Reproductive Biology
j o u r n a l h o m e p a g e : w w w . e l s ev i er . c o m / l o c a te / ej o g r b
somewhatwhentheoffspringreachedtoddlerhood,morethan4 outof10womenstillfulfilledthediagnosticcriteriaforDSM-IV insomniatwoyearspostpartum[6].
Thepostpartumperiodisalsomarkedbyanincreaseinphysical complaints,although thereasonsforthis havenotbeenclearly explained [7–9]. While the physical and physiologic changes aroundpregnancyandbirthmaybeplausiblecausesofpoorsleep, anotherpossibilityis thatchronicinsomnia mayleadtoa new onsetofbodilypain.Thelinkbetweensleepandpainhasbeen investigatedextensivelyoverthepastfewdecadesinthegeneral population.Althoughthedirectionofcausalityisnotentirelyclear, andismostlikelybi-directional,severallinesofevidencepointto sleep problems being the primary antecedent. This includes evidence that insomnia exacerbates existing pain and predicts new-onset pain[10–13]. Additionally, studies demonstratethat sleep quality predicts pain severity the following day. Several studies have also demonstrated an association between sleep
complaints and physical symptoms in postpartum women. For example, two Korean studies found sleep disturbance among womentobecloselyrelatedtopostpartumfatigue[14,15].
Onepossiblemechanismwhichmightexplainthelinkbetween sleepandbodilypainisco-occurringmentalhealthproblems[16].
Women in the postpartum period are at increased risk of developing depressive disorders, and both sleep problems and pain are closely interrelated with depression in the postnatal period [17]. Therefore, there is a need to clarify the relative contributionofdepressionwhenpoorsleepimpactsthedevelop- mentofbodilypaininthepostpartumperiod.Maternalhealthcare in thepostpartum years remains a neglected areaof women's health in general [18].Welack knowledgeboth withregardto sleepproblemsandbodilypainingeneral,butespeciallyinhow these factors are related and whether changes in levels of depression mayaccount for theseassociations. To thebestour knowledge,nostudieshaveexaminedtheprospectiveassociation
Fig.1.Participantflowofthestudy.
betweenchronicsleepproblemsandthedevelopmentofimpaired physicalhealthinpostpartumwomen.
Based on the above considerations, the overall aim of the current study was to examine if different classes of insomnia trajectoriesduringandafterchildbirtharelinkedtothedevelop- mentofsubsequentbodilypaintwoyearspostpartum.Wealso aimedtoexploreifanyassociationcouldbeexplainedbypostnatal depressivesymptomsandotherpotentialconfounders.
Methods
Studypopulationanddesign
TheAkershusBirthCohortisalongitudinalquestionnairestudy targetedatallwomengivingbirthatAkershusUniversityHospital inNorway.Thehospitalservesapopulationof350,000fromboth urbanandruralareas.Allwomenscheduledtogivebirthatthe hospital were approached in gestational week 17 when they underwentroutinefetalultrasound.Womenwereincludedifthey gave consent to participate and were able to complete a questionnaireinNorwegian.TherecruitmentlastedfromNovem- ber2008untilApril2010.Consentingwomencompletedthefirst questionnaireat gestationalweek17, and thereafter received a questionnaireby mail at week 32 of pregnancy, 8 weeks after delivery,and2yearsafterdelivery.Intotal,2943womenreturned the second questionnaire, 2217 women returned the third questionnaireand2055womenreturnedthefourthquestionnaire.
The current study only included women who completed the baselineandthreefollow-upquestionnaires.Therefore,thefinal study sample in the current study consisted of 1480 women, representingaparticipationrateof32%ofthe4662womenwho originallyconsentedtoparticipate,and 72%ofthewomenwho returnedthefourthquestionnaire.SeeFig.1 foraflowchartof participants.
Instruments Insomnia
The Bergen Insomnia Scale (BIS) [19] was used to assess insomniaatallthreefollow-upassessments.TheBISincludessix itemsthatcorrespondtothediagnosticcriteriaforinsomniainthe DSM-IV-TR.Eachitemisscoredusingascalefrom0to7,wherethe respondents specify the frequency of the various insomnia symptomsintermsofdaysperweek.Thefirstfouritemsassess sleepimpairment(DSM-IV-TRcriterionAforinsomnia),andthe lasttwoitemsmeasuredaytimesleepinessortiredness(affecting school/workorprivatelife)anddissatisfactionwithsleep(DSM- IV-TRcriterionBforinsomnia).TheBIShasascoringrangefrom0 to 42, where higher scores correlate with more symptoms of insomnia.TheBIShaspreviouslydemonstratedgoodpsychometric properties[19].
Bodilypain
Thebodilypainscale,derivedfromthePrimaryCareEvaluation ofMentalDisorders(PRIME-MD)[20],wascompletedbywomen atthetwolastfollow-upperiods,andincludedthefollowingfive painlocations (ratedno/yes):stomachpain, back pain, pain in arms/legs/joints, menstrual pain/problems, and pain/problems duringsexual intercourse. In the current study, thePRIME-MD bodilypain subscale was used both continuously and dichoto- mously,thelatterbyemployingacutoffatthe90thpercentile,as anindicationofahighbodilypainload.
Backgroundinformation
Demographic information collected at week 17 included maternal age, marital status (married or cohabitating versus
single/widowed/divorced),numberofpreviouschildren(parity), andlevelofeducation(elementaryschool,completedhighschool, orhighereducation).Body-massindexwasassessedbothatweek 17andweek32andwascalculatedfromweight(kg)dividedby squaredheight(m2).
Depression
TheEdinburghPostnatalDepressionScale(EPDS)[21,22]was used to measure depressive symptoms at all three follow-up periods.TheEPDSisa10-itemquestionnairedevelopedtoscreen fordepressioninthepostpartumperiod;itaddressessymptoms present in the last seven days. The scale also has good psychometric properties during pregnancy [23]. Each question hasfouralternativeanswers,rangingfrom0to3.Inthecurrent study,theEPDSwasusedcontinuouslywithascoringrangefrom0 to30.
Statistics
Latentprofile analysis(LPA)was used toidentifysubsets of womenwhosharedasimilarpatternofresponsesontheBIS-scale acrossthethreetimepoints.LPAisaperson-centeredapproach, throughwhichweaimedtoestimatethenumberoflatentclasses thatcouldbeestablishedbasedonthewomen’sresponsestothe BIS.LPAisusedtoidentifyunobservablesubgroups,calledprofiles, and istherefore anapt analyticalapproach whentheaimis to identifysubtypesofconditionsorsymptomology.Forexample,it canbeusedtofinddistinct profilesbasedontheresponseson severaldifferentsymptoms,inordertodeterminethenumberof potentialsubgroups.Furthermore,thisinformationcanbeusedto classifyindividualsaccordingtotheirmostlikelylatentprofile,and usetheprofilemembershipininferentialstatistics.Thefollowing criteriawereusedtodeterminethenumberofclassestoretain:
AkaikeInformationCriterion(AIC),BayesianInformationCriterion (BIC andsample sizeadjustedBIC(adjBIC) [24].Also,we used measuresofentropy,aswellasVuong-Lo-Mendell-Rubin(VLMR) adjusted likelihood ratio test for testing the hypothesis that a modelwithonelessclassperformsjustaswell.
TheLPAwasdoneinaniterativemanner.Westartedwith1 class, and increasedthe number ofclasses until thefit criteria suggesteda good enoughmodel.LPAwas preferredoverlatent classanalysis,andwewantedtogettheestimatedmeansateach timepoint.Decidingontheretainedmodel,bothstatisticalcriteria andmeaningfulnessoftheclasseswereconsidered.Mplusversion 7.1wasusedfortheLPA-analyses(Muthén&Muthén,1998–2010).
Allotheranalyses wereperformedusingthe SPSSstatistical softwarepackage,version23(SPSSInc.,Chicago,IL,USA).Negative binomialregressionanalyseswereusedtoexamineassociations betweenclassesofinsomniaandsomaticsymptoms.Ratherthan themore commonlyused logistic regressions(producingodds- ratio (OR)), we used negative binomial regressions (producing relativerisk(RR))whichprovidesmorecorrectestimateswhenthe prevalence of the outcome of interest (in this case somatic symptoms)isrelativelyhigh.ORscanoverestimateaneffectsize whentheoutcomesarefrequent[25].Bothcrude/unadjustedand adjusted analyses were conducted. The adjustment variables included were maternal age, education, marital status, parity, BMI,symptomsofdepression(T1-T3),andsomaticsymptomsat T2.Asasensitivityanalysis,allregressionmodelswererepeated excluding individuals scoring above the 90thpercentile on the somaticsymptomsscale(PRIME-MD)atT2.
Ethics
Allwomenaskedtoparticipateweregivenwritteninformation explaining the purpose of the study and informed that
participationwasvoluntary.Informedconsentwasobtainedfrom all participants. The study was approved by the Regional Committeefor Ethics in Medical Research in Norway, approval numberS-08013a.
Results
Samplecharacteristics
Thestudysampleincluded1480women,withameanageof 31.6(SD=4.5).Nearlyallwomen(97.9%)weremarriedorliving with a partner, and a majority of the sample (72.5%) had an educationallevel beyond high school.The mean BMI was 24.5 (SD=4.5),and79.6%reportedthatthiswastheirfirstpregnancy.
Ananalysisofthebackgroundfactorsbetweenrespondersand non-responders showed that women dropping out after the baselineassessment(week17ofthepregnancy)weresignificantly younger,hadlesseducation,andweremorelikelytobedivorcedor separated,comparedtothewomenwhoalsoparticipatedatwave four(thecurrentsample)(allPs<0.001).Nosignificantdifferences wereobservedforanyofthesleepmeasuresbetweenthosewho dropped out and those who completed all of the follow-up assessments.
Classesofinsomnia
Atotal offivedifferentLPA-modelswerecompared, ranging fromoneclass tofive classes(see Table1 for fitindices across models).TheAIC,BICandadjustedBICweremarkedlylowerforthe two-classsolutioncompared totheone-class solution,withan entropyof0.735.Also,theVLMRAdjusted-LRTindicatedthatthe two-class solution was significantly better than the one-class solution(p<0.0001).Increasingthenumberof classestothree, lowered the fit indices further, increasing the entropy slightly (0.766), and the VLMR Adjusted-LRT was again significant (p=0.0004). There was onlya slightdecrease in the estimated fitindiceswhenincreasingto4classes,andtheentropydropped slightly (0.750) but the VLMR Adjusted-LRT was significant (p=0.0069). Allowing for five classes did not improve the fit indices;theentropydroppedsubstantially(0.667);andtheVLMR Adjusted-LRTwasnon-significant(p=0.3136).Forpurposesofthis study,themodelwiththreeclasseswasretained,andispresented inFig.2.Thethreeclassmodelidentifiedonemajorgroup(55.6%) withalowBISscoresacrossallthreetimepoints,onegroupwith intermediateBISscores(32.9%),andasmallergroup(11.5%)with higher BIS scores across all 3 time points. Inclusion of age, education,parity,andmaritalstatusascovariatesyieldednearly identicalresults,andthuswerenotincludedinthefinalmodel.
Predictorsofsomaticsymptomsatyear2postpartum(T3)
Aseriesofregressionanalyseswereconductedtoexamineto whatextentdifferent classesof insomnia trajectories predicted subsequent onset of bodilypain at T3 (year 2 postpartum). As
detailedinTable2,comparedtoClass1(lowscoreoninsomnia fromT1-T3),individualsinClass3(highinsomnialoadonallthree points)hada2.75-foldincreasedriskofreportingahighloadof painatT3.BeingclassifiedinClass2wasassociatedwith2.16-fold increased risk of pain at T3. Adjusting for demographics and lifestylebehaviorsdidnotreduceany oftheassociations,while adjusting for depression (T1-T3) substantially attenuated the associations. Including adjustmentfor bodilypain at T2 (eight weeks postpartum) further reduced the magnitude of the associations, but Class 2 and Class 3 of insomnia remained stronglyassociatedwithonsetofbodilypaininthefullyadjusted models(seeTable2fordetails).
Sensitivityanalyses
To further explorewhether theinsomnia predicted onset of bodilypainatT3,allregressionanalyseswererepeatedthistime excluding individuals scoringabove the90thpercentile onthe bodilypain subscale (PRIME-MD)at T2.As shownin Fig.3,all associationsbetweenbothClass2andClass3andtheonsetofpain atT3remainedsignificantintheanalyses.Forexample,eveninthe fullyadjustedmodel,bothClass2andClass3wereassociatedwith a1.8to1.9-foldincreasedriskoflateronsetofabodilypain(see Fig.3fordetails).
Comment
In thislongitudinalpopulationbasedstudyfrompregnancy untiltwoyearspostpartumwefoundthatbothintermediateand highlevels of chronicinsomnia frompregnancyto postpartum were associated with a later onset of subsequent bodily pain.
Depressionaccountedforsomeoftheassociations,butevenwhen adjustedfordemographicvariables,depressivesymptomsaswell asprevioussymptomsofpain,anindependenteffectofchronic insomniaremained.Insomniawasrelativelystablefrompregnan- cyuntiltwoyearspostpartum,withthreelatentclassesdescribing thetrajectoriesbest;onestablelow,onestableintermediateand one stable high. Thelattercomprised 11.5% of thesample, and intermediatehigh32.9%ofthesample.
While we are not awareof other longitudinalstudies using trajectoriesofinsomniasymptomstopredictlaterphysicalhealth, thecloselinkobservedbetweensleepandpainsymptomswasin line with previous cross-sectional findings. While the causal pathwaysbetweeninsomniaandimpairedphysicalhealthcannot be ultimately determined using an observational design, the temporalassociationssuggestthatinsomniaprecedestheonsetof pain,and,thus,isnotaconsequenceofphysicalhealthcomplaints.
Intermsofmechanismsofaction,weexaminedseveralfactors that mightexplain thelinkbetweenimpairedsleepand bodily pain.WefoundthatneitherbackgroundfactorsnorBMIwereable to substantially attenuate any of the observed associations.
However, as expected, depression was an important factor in linkingsleeptopain,reducingtheRRwith23%to56%inthestable intermediate and stable highclasses of insomnia, respectively.
Table1
Goodness-of-fitindicesacrossthelatentprofileanalysis(LPA)models.
Numberof classes
AIC BIC Adj.BIC Entropy VLMRAdj.
LRT
Lowestestimatedprobabilityofclass membership
Highestestimatedprobabilityofclass membership
1 29047.710 29078.845 29059.786 N/A N/A N/A N/A
2 28388.361 28440.252 28408.487 0.735 p<0.0001 0.885 0.939
3 28280.120 28352.768 28308.296 0.766 p=0.0004 0.843 0.922
4 28218.304 28311.709 28254.532 0.750 p=0.0069 0.791 0.913
5 28170.640 28284.801 28214.917 0.667 p=0.3136 0.745 0.847
AIC(AkaikeInformationCriterion);BIC(BayesianInformationCriterion),VLMRAdj.LRT(Vuong-Lo-Mendell-Rubinadjustedlikelihoodratiotest).
Evenwiththeadditionalcontrolforpreviouspainsymptomsand by excluding participants with comorbid pain eight week postpartum,couldnotsignificantlyreducethecloseassociation betweeninsomniaandthelateronsetofbodilypain.
There are some methodological limitations that should be mentioned. First, data on both sleep, pain and depressive symptoms were based on self-reported instruments and not through a clinical evaluation or use of objective measures.
Although the authors did have access tothe women’s clinical records, these didnot provideany information on these exact domains,whichotherwisewouldhavereducedthepotentialbias in observer ratings. While some important confounders were controlled for, other variables that could have influenced the association, such as other maternal psychopathology beyond depressivesymptoms,wereleftunexplored.Moreover,whilethe researchsamplewaslarge,theresponserateacrossallthreetime pointswasnothigh,whichmaylimitthegeneralizabilityofthe sample. Unfortunately, the problem with non-participation in surveyresearchseemstobeontherise[26].Itshouldalsobenoted
thattherewerenotabledifferencesbetweentherespondersand non-responders,withrespondersbeingolder,moreeducated,and morelikelytobemarried/cohabitating.Ofnote,however,wasthat nodifferencesinsleepwereobservedinwomenwhocompletedall threewavescomparedtowomenwhodroppedoutafterT1orT2.
Thereareseveralstrengthsinthepresent study.Thecurrent studyisoneofthelargeststudiesofsleepduringpregnancy,and,to thebestofourknowledge,theonlyprospectivestudyexamining theeffectofmaternalsleepfrompregnancyintotoddlerhood,on thedevelopmentofsomaticcomplaints.Moreover,thequestion- nairesusedinthecurrentstudyarewell-validatedinstruments, and the self-report sleep measure (BIS) has been shown to correspondwellwithobjectivesleep measures, includingpoly- somnography(PSG)[19].Althoughself-reportedsleepparameters typicallydiffer fromthoseobtainedfromobjectiveassessments [27], recent studies have shown that such self-report sleep assessments can be recommended for the characterization of sleepparametersinbothclinicalandpopulation-basedresearch [28].Still,theBIShasnot beenvalidatedforsleepproblemsin Fig.2.Latentprofilesacrosstimeacrosstimepoints.Stablelow(55.6%),stableintermediate(32.9%),andstablehigh(11.5%).
Table2
InsomniatrajectoriesfromT1toT3asriskfactorsforonsetofbodilypainatyear2postpartum(T3).
Insomniatrajectories(classes)fromT1toT3 Stablelow
(Class1)
Stableintermediate (Class2)
Stablehigh (Class3)
Adjustmentvariables RR 95%CI RR 95%CI RR 95%CI
Crudemodel 1.00 – 2.16 1.75–2.66 2.75 2.11–3.60
+Age,education,parity,maritalstatus,BMI(T1) 1.00 – 2.17 1.72–2.74 2.54 1.86–3.48
+Symptomsofdepression(T1,T2andT3) 1.00 – 1.86 1.46–2.38 1.79 1.26–2.54
+Bodilypain(T2) 1.00 – 1.75 1.37–2.23 1.63 1.15–2.32
RR:Riskratio;CI:confidenceintervals.
pregnancy.Similarly,althoughtheEPDSdoesnotprovideaclinical diagnosisofdepression,it iswell suitedtoassesssymptomsof depressionamong Norwegianpostpartumwomen[22],and the useofthecontinuousscale(asusedinthecurrentstudy)isalsoin line with the recommendations for use in population-based research[29].
Clinicalimplications
The main finding in the current study was that chronic insomniawasassociatedwithincreasedriskdevelopingpostpar- tumpainsymptoms.Giventhehighratesofsleepproblemsduring pregnancyandthepostnatalperiod,combinedwiththefactthat both insomnia and bodily pain have been linked to increased disability[30], theneed toimprovesleepthis patient groupis evident.Bothpharmacological[31]andnon-pharmacological[32]
interventionsforinsomniaandbodilypainhavebeenthoroughly examined.With regardstobehavioral interventionswhichnow largely are considered the treatment of choice for persistent insomnia[33],cognitive-behavioraltherapyaddressingbothpain and sleep,hasbeenfoundtobe effective[32].Future research should examine to what extent low threshold interventions addressing comorbid sleep and pain may be effective, as internet-basedself-helptreatmentshaveshownpromisingresults intreatingbothconditionsindividually[34–36].Moreover,given thesignificantcontributionofdepressivesymptomsinexplaining theobservedsleep-painassociation,wealsorecommendscreen- ing for depression during and after pregnancy, in addition to adequatelyidentifying,preventingandtreatinginsomniaforthis population.
Conflictofinterest
Theauthorsreportnoconflictsofinterest.
Funding
ThestudywassupportedbytheNorwegianResearchCouncil, projectnumber191098.Thefundershadnoroleinstudydesign, datacollectionandanalysis,decisiontopublish,orpreparationof themanuscript.
Authorcontributions
AuthorsBSandMHdraftedthemanuscript,andAuthorsBSand JCSconductedthestatisticalanalysis.AuthorMEGwasresponsible for conception and design of the study and was involved in acquisitionofdata.AuthorsKPandMEGgavecriticalrevisionof themanuscriptforimportantintellectualcontent.Allauthorsread andapprovedthefinalmanuscript.
Acknowledgements
Theauthorsthankthewomenwhovolunteeredtheirtimeto participateinthisstudy.
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