Prevalence and Outcomes of Breast Milk Expressing in Women With Healthy Term Infants

A Systematic Review

Helene M Johns; Della A Forster; Lisa H Amir; Helen L McLachlan

Disclosures

BMC Pregnancy Childbirth. 2013;13(212) 

In This Article

Discussion

Although there is some commentary about an increase in breast milk expressing in the literature, actual measurement of the phenomena is quite limited. In addition, expressing breast milk is anecdotally less common in countries where there are more generous maternity leave provisions in terms of length of financial support, but there is limited evidence in the literature to support this. Two studies, one in Australia and the other in Singapore provide the only data actually documenting an increase in expressing over time.[2,6] Other authors discuss the prevalence of expressing and describe a preponderance of the practice.[1–6,27] This suggests that breast milk feeding solely at the breast is actually quite rare, at least in the developed world. Some breast milk expressing deserves consideration as incidental, something a mother might do only on occasion, for example when she needs to go out without her baby, when introducing infant cereal, when the infant is ill or unable to attach or is refusing the breast. We know that expressing breast milk has become more common, clarification of the amount, the proportion and the frequency of expressing and breast milk feeding is necessary before we can properly explore the implications of this relatively unexplained shift away from the breast.

Although concluding remarks in the 2011 Cochrane review identify the relative effectiveness of hand expressing and less expensive breast pumps,[28] it is not surprising that regular scheduled expressing is associated with the use of electric breast pumps.[3] Hand expressing barely rates a mention in the literature about expressing breast milk, although breast pump use and ownership are commonly discussed.[2,31,54,55] Thorley describes breast pumps as a substitute for the skill of hand expression.[23] A recent paper from Flaherman et al. reports on an apparent positive effect of hand expressing when compared with bilateral electric pumping.[30] The authors discuss the possibility that hand expressing contributes to less awkwardness or embarrassment for the mother, who is more likely to be comfortable hand expressing than using a pump when others are present.[30] After the establishment of a mature milk supply however, a 2013 review of studies comparing different methods of milk expression,[37] identifies several that found electric breast pumping to be more effective than any other method in terms of milk volume obtained.[49,56,57] The let-down reflex, a physiological response that is the process by which milk becomes available for the baby, can be inhibited by stressful situations such as embarrassment.[58] This may also be the case when unfamiliar equipment such as the breast pump is used. Suggestions of unquantifiable benefits associated with teaching hand expressing are made by Morton as she cautions against an "over-reliance on mechanical interventions"[59] (p. 276). Maternal confidence may be enhanced by a more relaxed early postpartum experience. Ease with the mechanics of breastfeeding may be fostered for the woman who has had some experience handling her breasts to obtain milk, as she will have done when hand expressing. The confidence attained by the handling and the achievement of actually expressing, as well as the visualisation of her milk may reinforce such confidence as she has expressed simply, with her own hands and without the complication of any additional mechanisation.

Women express breast milk because of doubt about the adequacy of their milk supply.[36] Many do so because of initial difficulties establishing breastfeeding.[2,3,5,27] Maternal return to work has been identified as another reason.[3,5,27] Workplaces which provide options such as on-site childcare, lactation breaks for expressing and/or breastfeeding foster longer term breast milk feeding.[60] Focus on breast expression facilities may however encourage maternal return to the workforce at the cost of other initiatives, or at the cost of broader social change to support women to spend more time with their infants and by implication, breastfeeding. Elevated BMI, cultural differences and embarrassment about breastfeeding in public all contribute to increasing breast milk expression rates.[3,5,27,29,32,34]

Simple attribution of cause and effect is probably inadequate in any discussion of expressing and its impact on breastfeeding success and duration. Several authors appear to refer to 'any' expressing without specifying relative quantities or proportions of breast milk feeds given, from the breast or otherwise.[2,4,6]

Expressing may contribute to a parental focus on the measurement of breast milk. Such quantification of breast milk may undermine confidence about the adequacy of milk supply, and may be reflected in parental anxiety about not knowing how much milk the baby is obtaining when feeding directly from the breast.[31]

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