Methods of milk expression for lactating women
Abstract
Background
Breastfeeding is important for health. However, not all infants can feed at the breast and effective methods of expressing milk have not been adequately evaluated.
Objectives
To assess acceptability, effectiveness, safety, effect on milk composition, bacterial contamination of milk and cost implications of a range of methods of milk expression, including hand expression and manual, battery and electric pumps.
Search methods
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2007), CINAHL (1982 to July 2007), handsearched relevant journals and conference proceedings, scanned secondary references and contacted experts in the field.
Selection criteria
Randomised and quasi‐randomised controlled trials that compared one method or technique of milk expression or pumping with other(s), at any time after birth, and cross‐over trials that commenced at least 28 days after birth.
Data collection and analysis
Two authors independently assessed trial quality and extracted data. We sought additional information from the trial authors.
Main results
Twelve studies met the inclusion criteria of which six (397 mothers) provided data that could be used in the analyses. Compared with hand expression, one study found a significantly greater total volume of milk expressed over six days both with the electrical pump (373.10 ml, 95% confidence interval (CI) 161.09 to 585.11), and with the foot‐operated pump (212.10 ml, 95% CI 9.39 to 414.81); however, the difference found between the foot pump and the electric pump was not significant. Mothers provided with a relaxation tape produced a greater volume of milk at one expression than women not provided with the tape (34.70 ml, 95% CI 9.51 to 59.89). Simultaneous pumping took less time than sequential pumping in one study (3.50 hours/week, 95% CI 1.39 to 5.61). No evidence of difference was found in volume with simultaneous or sequential pumping, or for milk contamination, breastfeeding at discharge, fat content of milk, serum prolactin by method of pumping. Maternal satisfaction, adverse effects on mothers and economic effects of interventions were poorly reported.
Authors' conclusions
Mothers appear to obtain greater total volumes of milk in six days after birth using the electric or foot powered pump tested compared to hand expression, and a greater volume at one expression during the second week when provided with a relaxation tape. Simultaneous pumping takes less time compared to sequential pumping. Further research with larger numbers and more comprehensive reporting is needed, and mothers' reasons for expressing linked to their evaluation of effectiveness rather than market‐led research on equipment performance.
PICOs
Plain language summary
Methods of milk expression for lactating women
The World Health Organization recommends that infants be fed exclusively on human milk from birth to six months of age. Children who do not receive human milk are more likely to suffer health problems. Not all babies are able to feed at the breast because of prematurity, illness, abnormalities or separation from their mothers; these babies need expressed human milk. Mothers may also express milk for their own comfort if they have sore nipples or engorgement; to increase milk supply; or to leave milk if away from their baby. Possible adverse effects from expressing milk include injury to the mother and bacterial contamination that may affect the baby.
This review included 12 studies and six of these had data that could be used in the analyses. All the mothers in these six studies were mothers of infants in neonatal units in the USA, UK, Malaysia, Kenya and Nigeria. In one study, using the electric or foot‐operated pump provided a greater mean volume of milk than hand expression during a six‐day period in the first two weeks after birth. Simultaneous pumping of both breasts and sequential pumping gave similar volumes, though the time taken was different. In one study, mothers given a relaxation tape were more likely to produce a greater volume of milk at one expression. One small study found that hand‐expressed and pump‐expressed milk had a similar incidence of milk contamination. All studies were small and results may not apply to pumps other than those tested.
No study asked mothers if they had achieved their own goals for expressing milk. None of the studies examined costs involved with different methods. Eight of the 10 studies that evaluated pumps or other products had support from the manufacturers. The available evidence indicates that low cost measures such as relaxation, breast massage, frequency of expressing or pumping, and simultaneous pumping, if acceptable to mothers, may be effective in assisting mothers to provide expressed milk. Not all the studies mentioned if basic supports were provided, particularly for mothers with hospitalised children, including access to food and fluid, a place to rest near their baby, and knowledgeable health workers. Whatever method of expression is used, mothers need to feel valued and supported.
