1 1 WhyisLaborPainfulinHumans? LaborPain - - PDF document

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Lecture17:Lactation Lecture17:Lactation

• LaborPain

LaborPain

• MorphologyoftheBreast

MorphologyoftheBreast

• HormonalControlof

HormonalControlof Lactation Lactation

• MilkComposition

MilkComposition

• BenefitsofLactation

BenefitsofLactation

• EnergeticsofLactation

EnergeticsofLactation

BehavioralBiologyofWomen" 2006

WhyisLaborLonginHumans? WhyisLaborLonginHumans?

Stage1 Stage2

• Dilationand

Dilationand Effacementofcervix Effacementofcervix

• Mean=14hoursin

Mean=14hoursin firstbirth firstbirth

• Expulsionoffetus

Expulsionoffetus

• Mean=50minutesin

Mean=50minutesin firstbirths firstbirths

• 20minutesinlater

20minutesinlater births births

WhyisLaborLonginHumans? WhyisLaborLonginHumans?

• !"#$%&&'&()

'$ !"%)&

WhyisLaborPainfulinHumans? WhyisLaborPainfulinHumans?

Thesizeoffetalheadgoingthroughpelvis?

WhyisLaborPainfulinHumans? WhyisLaborPainfulinHumans?

Theneedforthecervixtodilateto10cmto accommodatethelargefetalhead?

HowisHumanBirthDifferent? HowisHumanBirthDifferent?

*! *! !( !( ' ' $$$!& $$$!& $&&'+$! $&&'+$!, , #&&' #&&' +$ +$ $!&'('$ $!&'('$ '+''$ '+''$ && && $-)! $-)! ./ ./

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• Humansspendsignificantlymoretimein

Humansspendsignificantlymoretimein thelaterstagesofdilationwhenpainis thelaterstagesofdilationwhenpainis greatest. greatest.

WhyisLaborPainfulinHumans? WhyisLaborPainfulinHumans?

• Apesprobablyexperiencerelativelylittle

Apesprobablyexperiencerelativelylittle painduringlaborbecausetheyhave painduringlaborbecausetheyhave relativelylittledilation relativelylittledilation

LaborPain LaborPain

• Whydoesrelaxation

Whydoesrelaxation help? help?

• Autonomicnervous

Autonomicnervous system system

> > Parasympathetic

Parasympathetic (relaxation) (relaxation)

> > Sympathetic(fightor

Sympathetic(fightor flightresponse) flightresponse)

AssistedBirthinHumans AssistedBirthinHumans

• Birthisroutinelyperformedwithassistancein

Birthisroutinelyperformedwithassistancein humans. humans.

• Emotionalsupporttothemother

Emotionalsupporttothemother

• Mechanicalassistance

Mechanicalassistance

BirthSupport( BirthSupport(doula doulaeffect) effect)

Sosa,etal.(1980) Sosa,etal.(1980)

• 1

2(

• 3)+'

4!& 4

• AssistedBirthinHumans

AssistedBirthinHumans

• Birthisroutinelyperformedwith

Birthisroutinelyperformedwith assistanceinhumans. assistanceinhumans.

• Emotionalsupporttothemother

Emotionalsupporttothemother

• Mechanicalassistance

Mechanicalassistance

> > Maybeparticularlyimportant

Maybeparticularlyimportant forbreechbirths(2 forbreechbirths(2" " 4%of 4%of births) births)

(Gregoryetal.1999)

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MorphologyoftheBreast MorphologyoftheBreast

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BreastDevelopment BreastDevelopment BreastChangesduringPregnancy BreastChangesduringPregnancy ( (mammogenesis mammogenesis) )

• Estrogencausesgrowthofductsand

Estrogencausesgrowthofductsand proliferationofalveoli proliferationofalveoli

BreastChangesduringPregnancy BreastChangesduringPregnancy

• Estrogencausesgrowthofductsand

Estrogencausesgrowthofductsand proliferationofalveoli proliferationofalveoli

• Progesteronecausesthealveolarmilk

Progesteronecausesthealveolarmilk glandstomature glandstomature

BreastChangesduringPregnancy BreastChangesduringPregnancy

• Prolactin

Prolactin, , cortisol cortisolandgrowthhormoneturn andgrowthhormoneturn breastcellsinto: breastcellsinto:

> > Secretorycellsthatmakemilk Secretorycellsthatmakemilk > > Musclecellsthatwillsqueezemilkdown Musclecellsthatwillsqueezemilkdown throughducts throughducts

MorphologyofAlveolus MorphologyofAlveolus

• Siteofmilksynthesis

Siteofmilksynthesis

MorphologyofAlveolus MorphologyofAlveolus

• Siteofmilksynthesis

Siteofmilksynthesis

• Containedwithacapsuleofbasementmembranewhich

Containedwithacapsuleofbasementmembranewhich containscontractile containscontractilemyoepithelial myoepithelialcells. cells.

5 5

StagesofBreastMilkProduction StagesofBreastMilkProduction

• Mammogenesis

Mammogenesis:establishmentofglandular :establishmentofglandular morphologycapableofproducinglarge morphologycapableofproducinglarge quantitiesofmilk quantitiesofmilk

Mammogenesis

(completeat4mths)

StagesofBreastMilkProduction StagesofBreastMilkProduction

• Lactogenesis

Lactogenesis:establishmentofactively :establishmentofactively secretingmammarygland secretingmammarygland

Lactogenesis

(BeginsatParturition)

StagesofBreastMilkProduction StagesofBreastMilkProduction HormonesofLactation HormonesofLactation

• Galactopoiesis

Galactopoiesis:maintenanceofmilksecretion :maintenanceofmilksecretion

Galactopoiesis

Prolactin&MilkProduction Prolactin&MilkProduction

• Nipplestimulation

Nipplestimulation

Prolactin& Prolactin& Milk Milk Production Production

• Nipple

Nipple stimulation stimulation

• Hypothalamus

Hypothalamus stopsproducing stopsproducing prolactin prolactin" " inhibitingfactor inhibitingfactor (dopamine) (dopamine)

6 6

Prolactin& Prolactin& Milk Milk Production Production

• Hypothalamus

Hypothalamus stopsproducing stopsproducing prolactin prolactin" "inhibiting inhibiting factor(dopamine) factor(dopamine)

• Hypothalamus

Hypothalamus secretesVIP secretesVIP ( (vasoactive vasoactive intestinal intestinal polypeptide) polypeptide)

Prolactin&MilkProduction Prolactin&MilkProduction

• Nipplestimulation

Nipplestimulation

• Hypothalamusstops

Hypothalamusstops producingprolactin producingprolactin" " inhibitingfactor inhibitingfactor

• Hypothalamussecretes

Hypothalamussecretes VIP( VIP(vasoactive vasoactive intestinalpolypeptide) intestinalpolypeptide)

• Inresponse,

Inresponse, Prolactin Prolactinis is secretedfrom secretedfrom lactotrophs lactotrophsinthe inthe anteriorpituitary anteriorpituitary

Prolactin&MilkProduction Prolactin&MilkProduction

• Nipplestimulation

Nipplestimulation

• Hypothalamusstops

Hypothalamusstops producingprolactin producingprolactin" "inhibiting inhibiting factor factor

• HypothalamussecretesVIP

HypothalamussecretesVIP ( (vasoactive vasoactiveintestinal intestinal polypeptide) polypeptide)

• Inresponse,

Inresponse, Prolactin Prolactin is is secreted secreted frmlactotrophs frmlactotrophs inthe inthe anteriorpituitary anteriorpituitary

• Prolactin

Prolactin stimulatesmammary stimulatesmammary glandstoproducemilk glandstoproducemilk

SucklingandProlactin SucklingandProlactin

• Increasedsuckling

Increasedsuckling producesincreasedmilk producesincreasedmilk production. production.

• Prolactin

Prolactinapproaches approaches levelofnon levelofnon" "lactating lactating womenin4 womenin4" "6hours 6hours

Prolactin ProlactininNon inNon" "Lactating Lactating Womenafterstimulation Womenafterstimulation

• 2$
• $0

*

• MilkLetdown&Oxytocin

MilkLetdown&Oxytocin

• Milkpassesfromalveoli,via

Milkpassesfromalveoli,via ducts,tothe ducts,tothe

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MilkLetdown&Oxytocin MilkLetdown&Oxytocin

• Milkpassesfromalveoli,via

Milkpassesfromalveoli,via ducts,tothe ducts,tothe

• Sucklingstimulatesmothers

Sucklingstimulatesmothers autonomicsensorynervesin autonomicsensorynervesin thebreast thebreast

Latchingon Latchingon Latchingon Latchingon

• Babieslatchonto

Babieslatchonto theareola, theareola, NOTthe NOTthe nipple nipple

MilkLetdown&Oxytocin MilkLetdown&Oxytocin

• Sucklingstimulates

Sucklingstimulates mothersautonomic mothersautonomic sensorynervesinthe sensorynervesinthe breast breast

• Sendsmessageto

Sendsmessageto hypothalamus hypothalamus

MilkLetdown&Oxytocin MilkLetdown&Oxytocin

• Sendsmessageto

Sendsmessageto hypothalamus hypothalamus

• Causesposterior

Causesposterior pituitarytoproduce pituitarytoproduce

• xytocin
• xytocin

MilkLetdown&Oxytocin MilkLetdown&Oxytocin

• Causesposteriorpituitaryto

Causesposteriorpituitaryto produceoxytocin produceoxytocin

• Stimulatesmusclecellsinbreast

Stimulatesmusclecellsinbreast tocontract tocontract

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MilkComposition: MilkComposition: Colostrum Colostrum

• Producedinfirstfewdays

Producedinfirstfewdays afterbirth afterbirth

MilkComposition: MilkComposition: Colostrum Colostrum

• Producedinfirstfew

Producedinfirstfew daysafterbirth daysafterbirth

• Highinprotein,low

Highinprotein,low infatandlactose infatandlactose (milksugar) (milksugar)

MilkComposition: MilkComposition: Colostrum Colostrum

• Richin

Richin immunoglobulins immunoglobulins(esp. (esp. IgA IgAand and IgG IgG) )

• Establishnormal

Establishnormal bacterialfloraof bacterialfloraof infant infant’ ’sdigestivetrack sdigestivetrack

• Providesepidermal

Providesepidermal growthfactorsforfinal growthfactorsforfinal maturationofinfant maturationofinfant gut. gut.

BreastMilkImmunity BreastMilkImmunity

• Immunoglobulins

Immunoglobulinsinbreastmilkprotects inbreastmilkprotects newbornsagainstinfectiousdisease newbornsagainstinfectiousdisease

9 9

BreastMilkImmunity BreastMilkImmunity

• Immunoglobulins

Immunoglobulinsinbreastmilkprotects inbreastmilkprotects newbornsagainstinfectiousdisease newbornsagainstinfectiousdisease

• Peyer

Peyer’ ’s spatchesinmaternalgut patchesinmaternalgut

BreastMilkImmunity BreastMilkImmunity

• Immunoglobulins

Immunoglobulinsinbreastmilkprotects inbreastmilkprotects newbornsagainstinfectiousdisease newbornsagainstinfectiousdisease

• Peyer

Peyer’ ’s spatchesinmaternalgut patchesinmaternalgut

• Lymphocyteslodgeinbreastandproduce

Lymphocyteslodgeinbreastandproduce IgA IgAinbreastmilkwhichcoatsbaby inbreastmilkwhichcoatsbaby’ ’s s intestinesandprohibitforeignobjectsfrom intestinesandprohibitforeignobjectsfrom gettingthrough gettingthrough

MilkComposition MilkComposition

• Foremilk

Foremilk— —milk milk storedinducts storedinducts

• Lowfat,lowprotein,

Lowfat,lowprotein, watered watered" "down down

• 1/3oftotalmilk

1/3oftotalmilk volumeeachnursing volumeeachnursing

MilkComposition MilkComposition

• Hindmilk

Hindmilk— —milk milkstoredinalveolarcells storedinalveolarcells andreleasedduringletdown andreleasedduringletdown

• Highfat,highprotein

Highfat,highprotein

BenefitsofLactation BenefitsofLactation

• IngestionbyNewbornHumans:

IngestionbyNewbornHumans:

• Lipidsinhumanmilkbetterabsorbedthancowsmilk

Lipidsinhumanmilkbetterabsorbedthancowsmilk

BenefitsofLactation BenefitsofLactation

• Ingestionby

Ingestionby NewbornHumans: NewbornHumans:

• Lipidsinhumanmilk

Lipidsinhumanmilk betterabsorbedthan betterabsorbedthan cowsmilk cowsmilk

• Aminoacidsincow

Aminoacidsincow’ ’s s milkdifficultfor milkdifficultfor newborn newborn’ ’slivertobreak slivertobreak downintoimportant downintoimportant proteins proteins

10 10

BenefitsofLactation BenefitsofLactation

• Ingestionby

Ingestionby NewbornHumans: NewbornHumans:

• Lipidsinhuman

Lipidsinhuman milkbetter milkbetter absorbedthan absorbedthan cowsmilk cowsmilk

• Aminoacidsincow

Aminoacidsincow’ ’s s milkdifficultfor milkdifficultfor newborn newborn’ ’sliverto sliverto breakdowninto breakdowninto importantproteins importantproteins

• Formofironnotwell

Formofironnotwell absorbed absorbed

BenefitsofLactation BenefitsofLactation

• Composition

Composition

• Cow

Cow’ ’smilklowin smilklowin nucleotides:25% nucleotides:25% human,6%cow human,6%cow

BenefitsofLactation BenefitsofLactation

• Composition

Composition

• Nucleotides

Nucleotides"" "" 25% 25% human,6%cow human,6%cow

• Processingofcow

Processingofcow’ ’smilk smilk destroys destroyslactoferrin lactoferrinand and transferrin transferrinandother andother immunologicalcells immunologicalcells

BenefitsofLactation BenefitsofLactation

• Composition

Composition

• Nucleotides

Nucleotides"" "" 25% 25% human,6%cow human,6%cow

• Processingofcow

Processingofcow’ ’smilk smilk destroys destroyslactoferrin lactoferrinand and transferrin transferrinandother andother immunologicalcells immunologicalcells

• Cow

Cow’ ’smilkhasdifferent smilkhasdifferent ratiosofcalcium, ratiosofcalcium, phosphorous,magnesium, phosphorous,magnesium, sodiumandzinc sodiumandzinc

BenefitsofLactation BenefitsofLactation

• InfantHealth:

InfantHealth:

• Bottlefedbabies

Bottlefedbabies have2xtheillness have2xtheillness rateand rateand

• 3xhospital

3xhospital admissionrateas admissionrateas breastfedbabies breastfedbabies

BenefitsofLactation BenefitsofLactation

• Breastfedbabies

Breastfedbabies havelowerrates havelowerrates

• f:
• f:
• Earinfection

Earinfection

• Pneumonia

Pneumonia

• Bronchitis

Bronchitis

• Vomiting

Vomiting

• Diarrhea

Diarrhea

11 11

BenefitsofLactation BenefitsofLactation

• Effectsinadults

Effectsinadults

• Lowerratesofdiabetes

Lowerratesofdiabetes

• Lowerratesofasthma

Lowerratesofasthma

• Lowercholesterollevels

Lowercholesterollevels

• Lowerheartdisease

Lowerheartdisease

• Lowerriskofbreast

Lowerriskofbreast cancer cancer

• Howdowecreateamore

Howdowecreateamore‘ ‘breast breast feeding feeding” ” friendlysociety? friendlysociety?

5 5 5 5 5 5 5 5 5 6 6 6 6

1'!&7 &$!8

FieldStudiesofBreastfeeding FieldStudiesofBreastfeeding

12 12

Months

Lactationinthe!Kung Lactationinthe!Kung

• Longinterbirthintervals

Longinterbirthintervals " " 44.1 44.1mths mths

• Patterningoflactation

Patterningoflactation

• 4.06bouts/hour

4.06bouts/hour

• 7.83min/hour

7.83min/hour

• 1.92min/bout

1.92min/bout

• Aschildgetsolder

Aschildgetsolder— — increaseinlength increaseinlength

• bouts

bouts

Lactationinthe!Kung Lactationinthe!Kung

• Lowerestradioland

Lowerestradioland progesteroneinnursing progesteroneinnursing mothers mothers

Lactationinthe!Kung Lactationinthe!Kung

• Lowerestradioland

Lowerestradioland progesteroneinnursing progesteroneinnursing mothers mothers

• Correlatedwithageof

Correlatedwithageof infantandmeantime infantandmeantime betweennursingbouts betweennursingbouts

Lactationinthe!Kung Lactationinthe!Kung

• Lowerestradioland

Lowerestradioland progesteroneinnursing progesteroneinnursing mothers mothers

• Correlatedwithageof

Correlatedwithageof infantandmeantime infantandmeantime betweennursingbouts betweennursingbouts

• Suggestedinter

Suggestedinter" "bout bout intervalkeyvariablein intervalkeyvariablein lactation lactationsubfecundity subfecundity

(Konner&Worthman)

13 13

Prolactin&NursingBoutLength Prolactin&NursingBoutLength

Prolactin Nursing Bout

Prolactin,#NursingBouts,&Time Prolactin,#NursingBouts,&Time EdinburghStudyofBreastfeeding EdinburghStudyofBreastfeeding

9$'0+

EdinburghStudy EdinburghStudy

• Studied27breastfeeding

Studied27breastfeeding and10bottlefeeding and10bottlefeeding mothers mothers

• Lactation/supplementation

Lactation/supplementation diaries diaries

• Measuredurinary

Measuredurinary hormones hormones

• Measureprolactininblood

Measureprolactininblood

ResumptionofOvarianFunction ResumptionofOvarianFunction

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Supplementation&OvarianFunction Supplementation&OvarianFunction ResumptionofOvarianFunction ResumptionofOvarianFunction EdinburghStudy EdinburghStudy

• Lactatingwomenresumedovarianfunctionlater

Lactatingwomenresumedovarianfunctionlater postpartumthandidbottlefeedingwomen postpartumthandidbottlefeedingwomen

EdinburghStudy EdinburghStudy

• Lactatingwomenresumedovarianfunctionlater

Lactatingwomenresumedovarianfunctionlater postpartumthandidbottlefeedingwomen postpartumthandidbottlefeedingwomen

• Frequencyofovulationincreasedwithtimeas

Frequencyofovulationincreasedwithtimeas lactationwasphasedout lactationwasphasedout

EdinburghStudy EdinburghStudy

• Lactatingwomenresumedovarianfunctionlater

Lactatingwomenresumedovarianfunctionlater postpartumthandidbottlefeedingwomen postpartumthandidbottlefeedingwomen

• Frequencyofovulationincreasedwithtimeas

Frequencyofovulationincreasedwithtimeas lactationwasphasedout lactationwasphasedout

• Rapidresumptionofovarianfunctioninbottle

Rapidresumptionofovarianfunctioninbottle feeders;gradualresumptioninbreastfeeders feeders;gradualresumptioninbreastfeeders

EdinburghStudy EdinburghStudy

• Lactatingwomenresumedovarianfunctionlater

Lactatingwomenresumedovarianfunctionlater postpartumthandidbottlefeedingwomen postpartumthandidbottlefeedingwomen

• Frequencyofovulationincreasedwithtimeas

Frequencyofovulationincreasedwithtimeas lactationwasphasedout lactationwasphasedout

• Rapidresumptionofovarianfunctioninbottle

Rapidresumptionofovarianfunctioninbottle feeders;gradualresumptioninbreastfeeders feeders;gradualresumptioninbreastfeeders

• Importanceofintroductionofsupplementary

Importanceofintroductionofsupplementary foods foods

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EdinburghStudy EdinburghStudy

• Lactatingwomenresumedovarianfunctionlater

Lactatingwomenresumedovarianfunctionlater postpartumthandidbottlefeedingwomen postpartumthandidbottlefeedingwomen

• Frequencyofovulationincreasedwithtimeas

Frequencyofovulationincreasedwithtimeas lactationwasphasedout lactationwasphasedout

• Rapidresumptionofovarianfunctioninbottle

Rapidresumptionofovarianfunctioninbottle feeders;gradualresumptioninbreastfeeders feeders;gradualresumptioninbreastfeeders

• Importanceofintroductionofsupplementary

Importanceofintroductionofsupplementary foods foods

• Womenwhoconceivedwhilenursingdecreased

Womenwhoconceivedwhilenursingdecreased thefrequencyto3orfewertimes/day. thefrequencyto3orfewertimes/day.

Lactation&Supplementation: Lactation&Supplementation: TheGambia TheGambia SupplementationandBreastMilk SupplementationandBreastMilk

• Gave130womensupplementincreased

Gave130womensupplementincreased caloriesfrom1568to2291+vitamin caloriesfrom1568to2291+vitamin

• Noeffectonbreastmilkvolume!!

Noeffectonbreastmilkvolume!!

SupplementationandBreastMilk SupplementationandBreastMilk

• Gave130womensupplementincreased

Gave130womensupplementincreased caloriesfrom1568to2291+vitamins caloriesfrom1568to2291+vitamins

• Noeffectonbreastmilkvolume

Noeffectonbreastmilkvolume

• Proteincontentslightlyincreased(6.6%)

Proteincontentslightlyincreased(6.6%)

• Milkfatincrease(7.9%)

Milkfatincrease(7.9%)

• Lactosedecrease(

Lactosedecrease(" "7.6%) 7.6%)

• Nochangeincalories

Nochangeincalories

• Vitaminincreasefromsupplement

Vitaminincreasefromsupplement

Prolactin&Supplementation Prolactin&Supplementation

16 16

GambianStudy GambianStudy

• Supplementationhadonlyasmalleffecton

Supplementationhadonlyasmalleffecton quantityandqualityofbreastmilk quantityandqualityofbreastmilk

• Supplementationhadadramaticeffecton

Supplementationhadadramaticeffecton prolactinlevels prolactinlevels

Prolactin Prolactin& & Lactational Lactational Amenorrhea Amenorrhea

• Highlevelsof

Highlevelsof prolactin prolactinassociatedwith associatedwith reducedabilityforeggtoproduce reducedabilityforeggtoproduce estradiol estradiol (inculture) (inculture)

• Evidencenowisrolemaybemoreindirect.

Evidencenowisrolemaybemoreindirect.

TheToba:PositiveEnergyBalance TheToba:PositiveEnergyBalance andHighNursingFrequency andHighNursingFrequency BreastFeedingHypotheses BreastFeedingHypotheses

• Howtoexplainvariationindurationof

Howtoexplainvariationindurationof postpartumperiodofinfecundity postpartumperiodofinfecundity

• NursingIntensityHypothesis

NursingIntensityHypothesis

• MetabolicLoadHypothesis

MetabolicLoadHypothesis

Valeggia&Ellison

NursingIntensityHypothesis

17 17

Nursingintensityhypothesis: Nursingintensityhypothesis:

• Relativemetabolicloadhypothesis:

18 18

Physicalactivitypostpartum Physicalactivitypostpartum

• !"!#
• n=70women

Focalsampling $ $%

• %

& &% $ & % ' ( $$ $& $% $' $( )*!+, ))-./01

Toba Tobawomenremainwell womenremainwell" "nourished nourished duringtheentirepostpartumperiod duringtheentirepostpartumperiod

• WHO’s“normal” range

"1.0 "0.8 "0.6 "0.4 "0.2 0.0 0.2 0.4 "15"14"13"12"11"10 "9 "8 "7 "6 "5 "4 "3 "2 "1 0 1 2 3

Monthsto1stmenses

MeanPBMI(±SE)

• Changesinenergybalanceinrelationto

timetofirstpostpartummenses

Firstmenses Averagen=45

19 19

Meandurationofpostpartumamenorrhea Meandurationofpostpartumamenorrhea 10 10 ( ( 4)months 4)months(n=122 (n=122) )

!Kung"likenursingintensity US"likenutritionalstatus

Lactational LactationalAmenorrheainToba AmenorrheainToba

• Mean=10.3months

Mean=10.3months

Valeggia&Ellison

Lactational LactationalAmenorrheainToba AmenorrheainToba

• Mean=10.3months

Mean=10.3months

• Highnutritionalstatusandhighnursing

Highnutritionalstatusandhighnursing intensity intensity— — leadstoshortperiodsof leadstoshortperiodsof lactational lactationalamenorrhea amenorrhea

Valeggia&Ellison

Lactational LactationalAmenorrheainToba AmenorrheainToba

• Mean=10.3months

Mean=10.3months

• Highnutritionalstatusandhighnursing

Highnutritionalstatusandhighnursing intensity intensity— — leadstoshortperiodsof leadstoshortperiodsof lactational lactationalamenorrhea amenorrhea

• Thus,nursing

Thus,nursing intensityaloneisinsufficient intensityaloneisinsufficient explanation explanation

Valeggia&Ellison

Lactational LactationalAmenorrheainToba AmenorrheainToba

• Mean=10.3months

Mean=10.3months

• Highnutritionalstatusandhighnursing

Highnutritionalstatusandhighnursing intensity intensity— — leadstoshortperiodsof leadstoshortperiodsof lactational lactationalamenorrhea amenorrhea

• Thus,nursing

Thus,nursing intensityaloneisinsufficient intensityaloneisinsufficient explanation explanation

• Interactionbetweennursingintensityand

Interactionbetweennursingintensityand nutritionalstatus nutritionalstatus

Valeggia&Ellison

Nexttime... Nexttime...

• Mother

Mother" "InfantBonding InfantBonding

• Fatherhoodandchangesin

Fatherhoodandchangesin paternalhormones paternalhormones

• Co

Co" "sleepingandSIDS sleepingandSIDS

• Parentingstylescross

Parentingstylescross" " culturally culturally

20 20

FieldStudiesofBreastfeeding FieldStudiesofBreastfeeding

Proximatedeterminants Proximatedeterminants

• f
• flactational

lactational amenorrhea amenorrhea Toba Tobawomennursetheirinfantsvery womennursetheirinfantsvery frequently frequently

• n=70

Nursingeventsduration Nursingeventsduration

• $
• &
• $+&

+ '+( $+$ $&+$% 2.,!1 )" ,./01

• Maternaldiet

Maternaldiet

• Onemainmeal+snacks

Onemainmeal+snacks

• Monotonous,calorie

Monotonous,calorie" "densediet densediet

• Richincomplexcarbohydratesandfats

Richincomplexcarbohydratesandfats (e.g.,frieddough,whitebread,noodles, (e.g.,frieddough,whitebread,noodles, rice,polenta) rice,polenta)

Determinantsofduration Determinantsofduration

• f
• flactational

lactationalamenorrhea amenorrhea

• Noassociationwithnursingbehavior(frequency,

Noassociationwithnursingbehavior(frequency, durationofindividualbouts,totaldurationof durationofindividualbouts,totaldurationof nursing,allregressionp>0.11) nursing,allregressionp>0.11)

• !

!

• "

" #$$%& #$$%&

21 21

'

• (&

Conclusion Conclusion

Thepatternofresumptionof Thepatternofresumptionof postpartumfertilitycouldbe postpartumfertilitycouldbe explainedbydifferencesin explainedbydifferencesinindividual individual metabolicbudgets metabolicbudgets. .