Table 4 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 |
|---|---|---|---|---|---|
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 |
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 | ||
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 | |||
1994–1998 | Non-representative sample | ||||
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 | ||||
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 | |||
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 | |||
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 | |||
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 | ||
- 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 | ||||
n = 587 | ? lower socio economic bias | ||||
2002–03 | No account of frequency of expressing | ||||
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 |
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 | ||
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 | |||
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 | |||
- 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) | |||
2008 | - Women’s experience of using breast pumps | Timing of questionnaire, possible recall bias | |||
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 |
n = 382 | |||||
2006–07 | Possible recall bias - interviews 6–9 months after birth | ||||
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 | |||
2006–2008 | Infant formula feeding 31% (66/210) to 18% (118/656) | Gestational age not indicated | |||
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 | ||||
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 |