What does the research tell us about breast compression when pumping for a term or preterm infant?
Summary of evidence concerning benefits of manual expression and breast compression during pumping
There is no role for breast compression during direct breastfeeding.
However, several studies suggest that manual expression of breast milk, either alone or in combination with pumping, leads to a higher fat content in individual milk samples, including colostrum. This is often attributed to the more effective expression of the low volume fattier portion of milk.
But literature does not specifically evaluate whether manual expression increases the overall 24-hour fat content compared to other expression methods. The focus in the studies is primarily on the fat content of individual expressions or the impact of combining manual techniques with pumping on milk composition. Variability in milk composition and synthesis rates throughout the day complicates definitive conclusions. "Hand express only vs pump only” comparisons are fewer and sometimes underpowered.
Rocha-Pinto et al 2025
This review identified various factors affecting breast milk macronutrient and energy content, categorized into maternal factors (eg age, nutritional status, lactation stage, circadian rhythmicity), obstetrical factors (eg parity, preterm delivery, pregnancy morbidities), and newborn factors (eg sexual dimorphism).
Specific findings include
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Milk from overweight and obese mothers is richer in energy and fat
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A progressive decrease in protein and increase in fat content occurs during a breastfeed
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Higher protein content is found in milk from mothers with hypertensive disorders
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Early milk from mothers who deliver prematurely has higher protein and energy content.
Cinar et al 2021
This systematic review investigated the effect of milk expression techniques (hand, manual and electric pumps) on the macronutrient content of human milk, and concluded that protein and lactose content are fairly consistent across expression methods. The studies that suggest fat content may be affected affected are not standardised e.g. for variables such as time between episodes of milk removal.
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No significant effect on the protein and lactose content of human milk expressed by manual pump, hand expression, or by an electric pump.
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Greater milk volumes are expressed using electric pump than by manual pump or hand expression.
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Fat content of foremilk expressed by a standard type pump and manual pump was significantly higher than by manual expression in certain studies. Other studies show no significant difference in the total fat content (e.g. 5.40%, 4.35% and 4.82%, respectively) of milk expressed by a manual pump, by hand and by an electric breast pump. One of the techniques which resulted in higher fat in the foremilk was hand expression or pump + manual maneuvers vs pump alone. However, whether this effect was due to milk expression techniques or other variables affecting the content of human milk (e.g. time between milk removal episodes) could not be clearly demonstrated in the reviewed studies due to heterogeneity and methodological weaknesses.
Becker et al 2016
This review of many randomized and quasi-randomized trials (including mothers of NICU and non-NICU infants) found that adding breast massage increased fat/lipid content when pumping; also that hand expression or a large electric pump delivered higher protein. But, crucially, they found no consistent evidence of difference in overall energy content between methods, and heterogeneity including in sample sizes made strong conclusions difficult.
Fouad et al 2014
This Egyptian study compared three techniques in mothers of 30-36 week gestational age preterm infants, at 7–14 days postpartum: hand expression alone, pumping alone, and a “Hand on Pump” (HOP) combination (pump + massage, compression, etc.). They found that the combined “HOP” method gave higher fat content than either hand or pump alone.
Morton et al 2012
In mothers of very preterm infants, combining hand techniques (massage, compression, hand expression) with pumping increases not only the volume but also the fat / energy content of expressed milk compared to pumping alone.
Recommended resources
Selected references
Becker GE, Smith HA, Cooney F. Methods of milk expression for lactating women. Cochrane Database Syst Rev. 2016;(9):CD006170. doi:10.1002/14651858.CD006170.pub4.
Cinar N, Suzan OK, Kaya O. Investigation of the effect of human milk expression techniques on milk content: a systematic review. Journal of Tropical Pediatrics. 2021;67(6):1-13.
Fouad G, Korraa A, Zaglol G. The effect of different techniques of breast milk expression in its fat content in mothers of preterm infants. Medical Journal of Cairo University. 2014;82:https://www.medicaljournalofcairouniversity.net/index.php/2014-2010-2022-2023-2017-2022/vol-2082-june-2016/1918-the-effect-of-different-techniques-of-breast-milk-expression-in-its-fat-content-in-mothers-of-preterm-infants.
Morton J, Wong RJ, Hall JY, Pang WW, Lai CT, Lui J, et al. Combining hand techniques with electric pumping increases the caloric content of milk in mothers of preterm infants. Journal of Perinatology. 2012;32:791-6.
Rocha-Pinto I, Pereira da Silva L, Silva D. Factors that may affect breast milk macronutrient and energy content: a critical review. Nutrients. 2025;17(2503):https://doi.org/10.3390/nu17152503.