Background
Methods
Results
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Prevalence of breast milk expressing;
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Methods of expressing;
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Reasons why women express their milk;
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Impact of expressing on breastfeeding outcomes;
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Other implications of expressing.
Prevalence of breast milk expressing
Author, year, country | Design | Location, participants, year of study and recruitment | Study aims and outcome measures | Results | Strengths/Limitations
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Geraghty et al. 2005 USA [1] | Retrospective cohort | Cincinnati, Ohio n = 346 2002 Random selection postal recruitment when infants were between 2 and 3 years old | Quantify breast pump use | 77% (182/236) ever used a breast pump | Large sample size |
Identify relationships between breast pump use and | No significant difference in expressing between 4 groups of mothers; those of | Clear differentiation between breastfeeding and breast milk feeding | |||
- singleton vs. multiple pregnancy | - term singletons | Periodic reports re. proportion of expressing versus breastfeeding (at 1 day, 3 days, 2 weeks and monthly until 6 months) | |||
- gestation at birth | - preterm singletons |
Retrospective data, possible recall bias, initial contact made when children between 2–3 years of age-requesting detailed information about infant feeding at 24 hrs, 3 days, 2 weeks and then at monthly intervals to 6 months.
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- breastfeeding outcomes | - term multiples |
Expressing methods not distinguished between hand, manual or electric pump
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- preterm multiples | |||||
- 68% (236/346) received at least some breast milk. | |||||
- 5% (12/236) exclusively expressed to feed – all mothers of premature babies | |||||
Binns et al. 2006 Australia [2] | Longitudinal | Perth, Western Australia | - Explore determinants of breastfeeding | - PIFS I 38% (211/556) expressing by 6 weeks | Large sample |
PIFS I n = 556 | - Measure and compare prevalence of expressing | - PIFS II 69% (405/587) expressing by 4 weeks | Comparison of similar groups 10 years apart | ||
1992–93 | - Expressing rates steadily decline after 6 weeks: |
Limited detail about expressed breast milk/ breastfeeding proportions.
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PIFS II n = 587 | 26% (145/556) at 24 weeks in PIFS I 28% (164/587) at 22 weeks in PIFS II |
Public patients only, perhaps not representative
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2002–03 |
Differing interview schedules – less clarity for comparison
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Recruited in hospital in early postpartum period | |||||
Labiner-Wolfe et al. 2008 USA [3] | Longitudinal | National study | - Reasons why women express | - Most common reason: for someone else to feed baby | Large sample |
n = 4606 | - Amount and prevalence of milk expression | - 85% (1329 /1564) between 1.5 and 4.5 months postpartum had expressed at some time since birth | Maternal recall previous 7 days | ||
2005–2007 | - Associated socio-demographic factors | - 68% (1015/1493) of this group had expressed in 2 weeks before survey, 25% (373/1493) regularly | Measures frequency of expressing (asked how many times expressed in previous 2 weeks and if expressed on a regular schedule) | ||
from IFPS II | - Expressing associated with: maternal employment, higher income, first breastfeeding experience |
Not nationally representative: Older, more educated, more likely to be white, employed, higher income, less likely to smoke. More likely to breastfeed and for longer
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Mail survey 2, 5 and 7 months postpartum | |||||
Shealy et al. 2008 USA [4] | Longitudinal | National study | Describe breastfeeding in first 12 months to identify: | - 0.06% of babies fed expressed breast milk exclusively – 2/3 of these ceased breast milk feeding by 4 weeks | Detailed analysis of feeding type/frequency/duration of individual feeds |
n = 2587 | - Prevalence of exclusive pumping and formula supplementing |
Limited data re. expressing – except when it was exclusive
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2005–2007 | - Patterns and trends in breastfeeding related to common advice given | ||||
from IFPS II | |||||
Monthly postal questionnaires | |||||
Clemons & Amir 2010 Australia [5] | Cross-sectional | State-wide study, Victoria | - Prevalence of breast milk expression | - 67% (602/898) had fully breastfed prior to hospital discharge | Large study |
n = 903 | - Demographic characteristics of women who express, why and how they do it | - 14% (125/898) had breastfed and expressed to feed their baby |
Possible selection bias (members of the Australian Breastfeeding Association)
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2008 | - Women’s experience of using breast pumps | - Of those whose youngest child was over six months 95% (628/661) fully breastfed for at least six months |
Timing of questionnaire, possible recall bias
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Online questionnaire sent to Australian Breastfeeding Association members who had an email address | - 4% (34/898) expressed and exclusively fed EBM | ||||
Baby any age | - 98% (885/903) ever expressed | ||||
Hornbeak et al. 2010 Singapore [6] | Retrospective cohort | Singapore | - Prevalence and patterns of breastfeeding in Singaporean Chinese mothers from birth to 6 months | - Initiation of breast milk feeding increased from 69% (144/210) in 2000-2001 to 82% (538/656) in 2006/2008 | Large representative sample of Chinese Singaporean mothers |
n = 3009 | - Exclusive expressing increased from 9% (18/144) in 2000-2001 to 18% (118/538) in 2006/2008 |
Limited detail about expressed breast milk/breastfeeding proportions.
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2006-2008 | - Direct breast milk feeding decreased from 34% (72/210) in 2000–2001 to 27% (142/656) in 2006/2008 |
Possible recall bias - recruitment 6–72 months after birth
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Recruited mothers of 6-72 month Chinese Singaporean children through Strabismus, Amblyopia and Refractive Error in Singaporean Children (STARS) Study |
Gestational age not indicated
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Mailed invitation | |||||
Face-to-face interview | |||||
Geraghty et al. 2012 USA [29] | Prospective longitudinal cohort | Cincinnati, Ohio | - Describe who commences expressing early | - 14% (8/59) commenced some expressing in first week | Prospective design assisting recall |
n = 60 | - Explore breastfeeding duration in women who express | - By four weeks: 63% (37/59) expressing | Initial weekly visits; used weekly and 24 hour recall to enquire about feeding and expressing | ||
2004–2007 | - Expressing had no effect on duration of breast milk feeding | Clear differentiation between ‘breastfeeding’ and ‘breast milk feeding’ | |||
Recruited face to face in first week after hospital discharge. |
Small study
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Recruitment of women who planned to breastfeed for 6 months or more
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Mothers recruited for study knew they were going to be assisted to pump and may have been more likely to be comfortable with this.
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Possible introduction of bias as weekly collection of breast milk was initiated at 1 week by research nurse using an electric breast pump
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Methods of expressing
Author, year, country | Design | Location, participants, year of study and recruitment | Study aims and outcome measures | Results | Strengths/Limitations |
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Binns et al. 2006 Australia [2] | Longitudinal | Perth, Western Australia | - Explore determinants of breastfeeding | - Approx. 60% (n = 1143) using manual pumps in both studies | Large study |
PIFS I n = 556 | - Measure and compare prevalence of expressing 1992-93 and 2002-03 | - Use of electric pumps increased by 31% in 10 years | Comparison of similar groups 10 years apart | ||
1992–93 |
Actual figures not given
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PIFS II n = 587 |
Public patients only, perhaps not representative
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2002–03 | |||||
Recruited in hospital in early post-partum period | |||||
Labiner-Wolfe et al. 2008 USA [3] | Longitudinal | National study | - Reasons why women express |
- Birth to 1.5 -4.5 months
| Large sample size |
n = 4606 | - Amount and prevalence of milk expression | 80% (105/1302) battery or electric 44% (573/1302) manual pump 14% (18/1302) hand | 3 mailed questionnaires seeking information re. feeding in previous fortnight - recall bias unlikely | ||
2005-2007 IFPS II | - Associated socio-demographic factors |
- Previous 3 months to 6.5-9.5 months
| Detailed information re. methods of expression over time | ||
Mail survey 2, 5 and 7 months postpartum | 73% (39/529) battery or electric) 33% (18/529) manual pump 13% (69/529) hand |
Not nationally representative, older, more educated, more likely to be white, employed, higher income, less likely to smoke. More likely to breastfeed and for longer
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Ohyama et al 2010 Japan [31] | Sequential crossover | Yokohama, Kanagawa | - Comparison of effectiveness and comfort of manual and electric breast expression in first 48 hours after birth | - Manual expressing associated with greater milk volume: net milk yield per woman 2 ml. | Limited other exploration of this area |
n = 11 | - Manual expression 2 ml (median; range: 0-12.6 ml.) |
Small study
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2003-2004 | - Electric expression 0.6 ml. (0-7.2 ml.) (P < 0.05). |
Infant gestation and health status not indicated
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Mothers of infants admitted to neonatal intensive care recruited in hospital soon after birth | - Manual pump associated with more reports of pain | ||||
Flaherman et al 2012 USA [32] | RCT | San Francisco & Sacramento, California | Comparison of hand and electric expression measured; | - At 2 months mothers assigned to hand expressing were more likely to be breastfeeding (97%, 47/48) than mothers assigned to breast pumping (73%,35/48) (RR:1.32, 95% CI 1.01,1.73) | Limited other exploration of this area, no previous studies linking type of expressing to breastfeeding outcomes |
n = 68 | - Milk transfer | Thorough discussion | |||
2007-2009 | - Breast pain |
Small study, final outcome assessment based on 48 participants
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Recruited12-36 hours after birth | - Breastfeeding confidence |
Possible bias- recruited infants experiencing feeding difficulty
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- Breast milk expression experience |
No control group
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- Breastfeeding rates at 2 months | |||||
Becker et al. 2011 UK [30] | Systematic review | International | - Assessment and review of randomised and quasi randomised trials comparing methods of milk expression any time after birth and crossover trials commencing at least 28 days after birth | - More milk with relaxation tape | Systematic review |
n = 642 women from 23 studies | - No difference in mean vol. with simultaneous or sequential pumping, or between manual and electric pumps studied |
Most studies specifically related to the care of the pre-term infant
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Reasons why women express their milk
Author, year, country | Design | Location, participants, year of study and recruitment | Study aims and outcome measures | Results | Strengths/Limitations |
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Dykes & Williams 1999 UK [34] | Longitudinal, phenomenological study | Northern England, | - Explore women’s experience of expressing particularly perception of adequacy of milk supply | - Beliefs re. adequacy of breast milk supply influenced by interplay of feeding management, infant behaviour, lactation physiology and maternal mental health. |
Small mono-cultural group
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n = 10 | |||||
1998 | |||||
Postnatal primiparas recruited face-to-face in hospital, home visits at 6, 8 &12 weeks | |||||
Binns et al. 2006 Australia [2] | Longitudinal cohort | Perth, Western Australia | - Explore determinants of breastfeeding | - Early breastfeeding difficulties, | Comparison of similar groups 10 years apart |
PIFS I n = 556 | - Measure and compare prevalence in expressing | - Engorgement, sore nipples, mastitis |
Mainly women who expressed to manage breastfeeding difficulties
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1992–93 | - Feed to be given by someone else |
Public patients only, perhaps not representative
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PIFS II n = 587 | - To store extra milk | ||||
2002–03 | - Father to feed | ||||
Recruited in hospital in early post-partum period. | - To increase supply | ||||
- Feeding/attachment problems | |||||
- To get baby to drink from a bottle | |||||
- Just to try it out | |||||
Labiner-Wolfe et al. 2008 USA [3] | Longitudinal cohort | National study | - Reasons why women express | - to allow someone else to feed | Large sample |
n = 3606 | - Amount and prevalence of milk expression | - maternal employment |
Not nationally representative Participants older, more likely to be educated, white, employed, higher income
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2005–2007 | - Associated socio-demographic factors | - to have an emergency milk supply | |||
from IFPS II | - no previous breastfeeding experience | ||||
- geographic location (Midwest Vs. West) | |||||
- embarrassed to breastfeed in public | |||||
Buckley 2009 USA [33] | Focus groups | Washington, DC | - Ascertain lactation consultant’s beliefs and experiences re. impact of breast pumps on breastfeeding practice | - Technological birth contributes to technological breastfeeding | Exploration of professional attitudes to change in feeding practice -no previous exploration of this area |
n = 12 | - Engorgement, plugged ducts, to increase supply, to stimulate the let-down reflex, to pull out inverted nipples. |
Small sample size
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Lactation consultants | - Return to work |
Volunteer participants
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Purposeful sampling | - Measuring milk, diminished confidence in ability to provide enough milk |
Date of study not indicated
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Clemons & Amir 2010 Australia [5] | Cross-sectional | State-wide study, Victoria | - Prevalence of breast milk expression | - Premature baby/sick mother or baby | Large study |
n = 903 | - Demographic characteristics of women who express, why and how they do it | - Attachment problems/not drinking well |
Possible selection bias (members of ABA)
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2008 | - Women’s experience of using breast pumps | - Advised |
Timing of questionnaire, possible recall bias
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Online questionnaire sent to Australian Breastfeeding Association (ABA) members who had an email address | - Not enough milk/To store extra milk | ||||
- Nipple pain | |||||
- Engorged breasts/mastitis | |||||
- So someone else can feed baby | |||||
- Maternal work | |||||
- Just to try it out | |||||
- To allow mother to drink alcohol | |||||
- Uncomfortable breastfeeding in public | |||||
Geraghty et al. 2012 USA [29] | Prospective longitudinal cohort | Cincinnati | - Duration of breast milk feeding | - Planned return to work by 6 months | Prospective design |
n = 60 | - Describe who commences expressing early |
Small study
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2004–2007 |
Recruitment of women who planned to breastfeed for 6 months or more
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recruited face to face |
Mothers recruited for study knew they were going to be assisted to pump and may have been more likely to be comfortable with this.
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Possible introduction of bias as weekly collection of breast milk was initiated at 1 week by research nurse using an electric breast pump
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Impact of expressing on breastfeeding outcomes
Author, year, country | Design | Location, participants, year of study and recruitment | Study aims and outcome measures | Results | Strengths/Limitations |
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Chapman et al. 2001 USA [45] | RCT | Hartford, Connecticut | Effects of expressing before the onset of lactation : | - No significant difference in milk transfer or breastfeeding duration between women who expressed breast milk and those who did not. |
Only women who had a caesarean section
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n = 60 | - on early milk transfer | - Primiparous women in pumping group breastfed for 5 months less than those in control group but this finding was not statistically significant. |
Study underpowered for primiparous women
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1997–1998 | - on subsequent breastfeeding duration | ||||
Convenience sample 8–24 hours post Caesarean Section | |||||
Schwartz et al. 2002 USA [42] | Prospective cohort | Detroit, Ann Arbor and Southfield, Michigan and Omaha, Nebraska | - Determine demographic, behavioural and clinical factors associated with weaning from breast in the first 12 weeks | - Michigan women (n = 711) who expressed breast milk were 3 times more likely to wean than those who didn’t (Hazard Ratio: 3.0 95% CI 1.3,6.7) | Large study |
n = 946 | - Nebraska women (n = 235) showed no association between pumping and weaning (HR: 0.6, 95% CI 0.3,1.5) |
Only measured to 12 weeks
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1994–1998 |
Non-representative sample
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Recruitment: |
Michigan group were recruited from an alternative birthing centre and were significantly more likely to be older than 30 years, have a bachelor’s degree, have 3 or more children and have had a vaginal birth
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Michigan - at birth centre orientation | |||||
Nebraska - on maternity leave application to large company | |||||
Ortiz 2004 USA [37] | Clinical audit | Burbank, California | - Duration of breast milk feeding related to a range of employee chosen lactation support options | - 98% (452/ 462) breastfeeding initiation | Large study over 4.5 years |
n = 462 | - 74% (246/332) expressed milk until infant at least 6 months |
Limited differentiation between breastfeeding and expressing / breast milk feeding
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1993–1999 | - 24% (81/332) expressed milk until infant at least 12 months |
No information re any other infant feeding/exclusivity of breast milk feeding
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Antenatal recruitment in workplace | - Mean age of infants at maternal cessation of pumping at work 6.3 months |
No consideration of options in the workplace to breastfeed at the breast
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Geraghty et al. 2005 USA [1] | Retrospective cohort | Cincinnati, Ohio | Measure breast pump use | Of breast milk feeding mothers: | Large sample size |
n = 346 | Identify relationships between breast pump use and: | - 10% (24/346) breastfed exclusively for a minimum of 6 months | Breastfeeding / breast milk feeding clearly differentiated | ||
2002 | - singleton vs. multiple pregnancy | - 16% (55/346) breastfed exclusively for duration of their breast milk feeding | Periodic reports re. proportion of expressing versus breastfeeding (at 1 day, 3 days, 2 weeks and monthly until 6 months) | ||
Random selection Postal recruitment when infants were between 2 and 3 years old | - gestation at birth | - 77% (182/236) expressed at some time in first 6 months |
Retrospective data, possible recall bias as participants were recruited 2 or more years post birth
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- breastfeeding outcomes | - 59% (140/236 ) ceased breast milk feeding by 6 months | ||||
Of the 140 women who had ceased breast milk feeding by 6 months, at the time point just prior to exclusive formula feeding: | |||||
- 76% (106/140) were either expressing exclusively or combining expressing with breastfeeding | |||||
- 24% (34/140) were breastfeeding | |||||
Early breastfeeding associated with a longer duration of breast milk feeding | |||||
Win et al. 2006 Australia [55] | Prospective cohort | Perth, Western Australia | - Investigate association between breast milk expression and breastfeeding duration | - Mothers who expressed at least once more likely to be breastfeeding at 6 months (RR: 0.71, 95% CI 0.52,0.98) | Prospective design assisting recall |
PIFS II |
Ever “expressed” / “any” breastfeeding
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n = 587 |
? lower socio economic bias
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2002–03 |
No account of frequency of expressing
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Recruited in hospital at birth. | |||||
Meehan et al. 2008 USA [43] | Quasi-experimental | Los Angeles, California | - Evaluation of program to facilitate breastfeeding for low income mothers | - Electric pump loan associated with more breastfeeding at 6 months. Mothers loaned a breast pump 5.5 times more likely to than those who hadn’t received one to not have requested formula by 6 months |
Limited reliability of proxy measurement to assess breast milk feeding prevalence or duration
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n = 208 | - Maternal request for formula from WIC program used as proxy measurement to give indication of partial breastfeeding | (OR: 5.5, 95% CI 2.0,15.1) |
No differentiation between breastfeeding and breast milk feeding
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2001 | |||||
Breast pump loan program for low income Women with Children (WIC) recipients | |||||
Fein 2008 USA [41] | Prospective cohort | National | - Examine strategies used to combine work and breastfeeding | Median duration of breast milk feeding associated with workplace practices: | Large National study |
n = 810 | - Identify strategies associated with enhanced breastfeeding intensity/longer duration | Prospective design | |||
2005–2007 | - expressing and breastfeeding (32.4 weeks) (n = 75) | Questionnaire design with 7 day recall | |||
from IFPS II | - breastfeed at the breast only (31.4 weeks) (n = 250) |
No description of feeding method away from workplace
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Recruitment via postal questionnaire in late pregnancy | - expressing only (26.3 weeks) (n = 75) |
Older, less educated, low income and women from racial/ethnic minority groups underrepresented
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- neither breastfeeding or expressing (14.3 weeks) (n = 128) | |||||
Clemons & Amir 2010 Australia [5] | Cross-sectional | State-wide, Victoria | - Prevalence of breast milk expression | - 27% (218/903) indicated that expressing had allowed them to breastfeed for longer | Large study |
n = 903 | - Demographic characteristics of women who express, why and how they do it |
Possible selection bias (members of ABA)
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2008 | - Women’s experience of using breast pumps |
Timing of questionnaire, possible recall bias
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online questionnaire | |||||
ABA members with internet addresses | |||||
Dabritz et al. 2010 USA [56] | Retrospective cohort | Yolo County, California | - Assess relationship between maternal experience in hospital and any breastfeeding at six months | - Almost exclusive breastfeeding at 6 months associated with not using a breast pump in hospital 77% (93/121) compared to 21% (25/121) who did use a pump in hospital (OR: 0.6 95% CI 0.3,1.0) |
Differentiation between breastfeeding and breast milk feeding unclear
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n = 382 | |||||
2006–07 |
Possible recall bias - interviews 6–9 months after birth
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Recruited in community after birth - 8 months | |||||
Hornbeak et al. 2010 Singapore [6] | Retrospective cohort | Singapore | - Record prevalence and patterns of breastfeeding in Singaporean Chinese mothers | - Breast milk feeding initiation and duration increased over time and were independently associated with higher maternal education, increased milk expression and complementary feeding | Large representative sample of Chinese Singaporean mothers |
n = 3009 | Changes between 2000–01 and 2006–08: |
Possible recall bias - recruitment 6–72 months after birth
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2006–2008 | Infant formula feeding 31% (66/210) to 18% (118/656) |
Gestational age not indicated
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Recruited mothers of 6–72 month Chinese Singaporean children through STARS | Breast milk feed initiation 69% (144/210) to 82% (538/656) | ||||
Mailed invitation | Expressed breast milk 9% (18/210) to 18% (118/656) | ||||
Combination feeding 26% (54/210) to 41% (269/656) | |||||
Geraghty et al. 2012 USA [29] | Prospective cohort | Cincinnati, Ohio | - Determine who expresses their milk by end of 4 weeks and how long they continue feeding | - Milk expression common in first month postpartum | Prospective design |
n = 60 | - Milk expression by 4 weeks did not significantly influence duration of breast milk feeding | Clear differentiation between breastfeeding and breast milk feeding | |||
2004–2007 |
Recruitment of women who planned to breastfeed for 6 months or more
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Participants enrolled in a research human milk bank recruited at home in first week postpartum |
Mothers recruited for study knew they were going to be assisted to pump and may have been more likely to be comfortable with this.
| ||||
Possible introduction of bias as weekly collection of breast milk was initiated at 1 week by research nurse using an electric breast pump
|
Implications for maternal health
Other implications of expressing
Author, year, country | Design | Location, participants, year of study and recruitment | Study aims and outcome measures | Results | Strengths/Limitations
|
---|---|---|---|---|---|
Clemons & Amir 2010 Australia [5] | Cross sectional | State-wide study, Victoria | - Prevalence of breast milk expression | - 17% (126/737) experienced nipple pain associated with pump use | Large study |
n = 903 | - Demographic characteristics of women who express, why and how they do it |
Possible selection bias (members of ABA)
| |||
2008 | - Women’s experience of using breast pumps |
Timing of questionnaire, possible recall bias
| |||
Online questionnaire sent to Australian Breastfeeding Association (ABA) members who had an email address | |||||
Baby any age | |||||
Li et al. 2010 USA [49] | Longitudinal cohort | National study | - Test infant ability to self-regulate intake – compare active sucking (breastfeeding) with passive feeding (EBM via bottle) | - Infants bottle fed early more likely to empty bottle/cup in late infancy | Large national longitudinal study Minimal reporting bias for exposure and outcome – 7 day retrospective recall |
n = 1597 | - Complete empting of bottle or cup in late infancy used to indicate self-regulation | - bottle a totally different feeding mode | Multivariate analysis | ||
2005–2007 |
Maternal report of feeding behaviour/bottle emptying - reporting error possible
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from IFPS II | |||||
Li et al. 2012[50] | Longitudinal cohort | USA | - Multi level analysis to estimate weight gain X type of milk & feeding mode at 3,5, 7.and 12 | - Among infants fed only breast milk, Breast milk fed infants gained 780g per month in the first year compared with breastfed infants who gained 729g | Large national longitudinal study Minimal reporting bias for exposure and outcome – 7 day retrospective recall |
n = 1899 | - Possible association between bottle feeding EBM and increased weight gain | ||||
IFPS II | |||||
2005-2007 | |||||
Geraghty et al. 2012 USA [28] | Retrospective cohort | Cincinnati, Ohio | - Examination of methods of maternal expression and infant consumption of breast milk | - All expressed, all babies fed some expressed milk | Limited other exploration of this area |
n = 40 | 95% (38/40) infants breastfed and EBM |
Small size
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2008 | 37% (15/40) fed EBM same day |
Retrospective data collection
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Outpatients attending breastfeeding clinic, recruited by mail | 30% (12/40) fed EBM same week |
Possible recall bias
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25% (8/40) fed EBM 1 and 4 weeks later | |||||
13% (5/40) fed EBM more than 4 weeks later |