Date of Submission: 19-Oct-2007
Name: Rajiv Bahl
Email Address: firstname.lastname@example.org
Personal Description: Occupation Medical Officer WHO
Conclusions of the Cochrane review on cup feeding for newborns unable to fully breastfeed are not supported by the findings
This recently published systematic Cochrane review based on four relatively small studies makes a general conclusion "Cup feeding cannot be recommended over bottle feeding as a supplement to breastfeeding because it confers no significant benefit in maintaining breastfeeding beyond hospital discharge and carries the unacceptable consequence of longer stay in hospital" (1). We feel that the findings of the review do not support this conclusion. Justification for this feeling is provided below.
The risk of infection should be an important consideration in the choice of feeding method. One of the major potential advantages of cup feeding over bottle feeding is in reducing the risk of infection, particularly in developing countries. All studies (2-4) included in the review except a small study from Brazil (5) are from developed countries and none has reported on the risk of infection. Although infection was included as an outcome in the protocol for this Cochrane review, the lack of data on this important outcome is not discussed.
On the outcomes on which data is presented, the number of participants in all studies is small. The total number of infants included in the meta-analysis on any breastfeeding is about 400. For comparison, in another study in term infants, Howard et al estimated that at least 700 infants would be needed to detect a 10% difference in breastfeeding cessation with 90% power and 5% significance level (6). The lack of significant effect on many outcomes could therefore have been just because of lack of statistical power. We think that the "lack of evidence of effect" cannot be taken as the "evidence of lack of effect".
The authors base their conclusions on their findings related to the lack of significant benefit of cup feeding beyond hospital discharge. However, all the studies included in the review were hospital studies with the primary outcomes limited to the time of hospital discharge. Only two studies reported effect at 3 months and one study at 6 months after discharge, as a secondary outcome. It is clear that even in these studies, sample sizes were not calculated, follow up was not complete and the quality of data cannot therefore be considered to be same as that for the primary outcome. Considering only the primary outcomes, there was a 18% non-significant benefit in any breastfeeding and 25% significant benefit in full breastfeeding rates associated with cup feeding. While these findings cannot be considered conclusive in favour of cup feeding, they are certainly indicative of a benefit. In any case, this is clearly not evidence of lack of benefit.
One of the possible reasons for only a modest benefit of cup feeding on subsequent breastfeeding could be the lack of compliance with the allocated intervention. Although the authors of the Cochrane review have recognized this, we think that they have not discussed it appropriately. For example, the researchers in the largest included study (2) considered the lack of compliance as the main limitation of their study which could have lead to an underestimate of the effect. Indeed, the researchers state in their paper that "Compliance analysis showed a significant increase in the prevalence of any breastfeeding with cup feeding (Odds ratio 21.09, 95% CI 2.62 to 169.75, P=0.004) with no significant difference in length of hospital stay (hazard ratio 0.82, 95% CI 0.58 to 1.17, P=0.27). Such compliance analysis needs to be interpreted with caution and highlight the need for further research." Further, they state that "Compliance differed between recruiting hospitals, the hospital with the better compliance has used cup feeding before, in the other it was introduced for the trial. Most peripheral hospitals had not used cup feeding before. Some staff had strong feelings against cup feeding?". The authors of the Cochrane review have not considered the lack of previous experience of staff with a new feeding method as one of the potential causes of lack of compliance with cup feeding.
The finding related to length of hospital stay (about a 15% increase in the duration of stay) needs to be interpreted with caution as it comes from a single study. Further, a possible reason for this could again be the lack of confidence of the treating physicians about the ability of the mother to feed the infant related to less experience in having used cup feeding relative to bottle feeding.
The conclusions and the plain language summary seem to indicate that the findings of this review are generalizable to all infants, in all settings. However, the studies reviewed included only those preterm infants who are not able to fully breastfeed. In this regard, it is important to consider the findings of an excluded study in term, healthy, breastfed infants (Howard et al), which show that for infants who received more than 2 supplemental feeds per day, cup feeding has distinct advantage over bottle feeding on breastfeeding duration. Also the findings may not be applicable to preterm infants in developing country settings.
Finally, we find the authors' conclusion that conducting further large, high quality RCTs on this issue may be a "futile undertaking" highly questionable. As stated above the problem of compliance in previous studies is an argument for doing better designed studies in health facilities that have experience in both cup and bottle feeding. Further, the importance of other factors like skin to skin contact, rooming in etc. should not be used an argument for not conducting research on appropriate feeding methods for infants who are not able to fully breastfeed. In our opinion, this meta-analysis underscores the need for further well-designed studies on this subject, in both developing and developed countries.
Rajiv Bahl, Constanza Vallenas, Jose Martines
Department of Child and Adolescent Health and Development
World Health Organization, Geneva
Disclaimer: The authors of this feedback are staff members of the World Health Organization. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions or the stated policy of the World Health Organization.
1. Flint A, New K, Davies MW. Cup feeding versus other forms of supplemental enteral feeding for newborn infants unable to fully breastfeed. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD005092. DOI: 10.1002/14651858.CD005092.pub2.
2. Collins CT, Ryan P, Crowther CA, McPhee AJ, Paterson S, Hiller JE. Effect of bottles, cups and dummies on breast feeding in preterm infants: a randomised controlled trial. BMJ Online First bmj.com 18 June 2004; BMJ, doi:10.1136/bmj.38131.675914.55.
3. Gilks J, Watkinson M. Improving breast feeding in preterm babies: Cup feeding versus bottle feeding. Journal of Neonatal Nursing 2004; 10:118-20.
4. Mosley C, Whittle C, Hicks C. A pilot study to assess the viability of a randomised controlled trial of methods of supplementary feeding of breast-fed pre-term babies. Midwifery 2001;17:150-7.
5. Rocha NM, Martinez FE, Jorge SM. Cup or bottle for preterm infants: effects on oxygen saturation, weight gain, and breastfeeding. Journal of Human Lactation 2002;18:132-8.
6. Howard CR, Howard FM, Lanphear BP, Ederly S, de Blieck EA, Oakes D, Lawrence RA. Randomized clinical trial of pacifier use and bottle-feeding or cupfeeding and their effect on breastfeeding. Pediatrics 2003;111:511-18.
Thank you for your comment on our review "Cup feeding versus other forms of supplemental enteral feeding for newborn infants unable to fully breastfeed".
The authors disagree with the statement from Rajiv B et al that the findings from the review do not support the conclusion. The conclusions were drawn from the evidence presented in the four included randomised control trials.
The author’s acknowledge that infection is important and thus, it was included as an outcome. A thorough literature search was undertaken on all published and unpublished studies and no data from either randomised nor non-randomised trials was found for this outcome. Several other papers from India (Gupta 1999, Malhotrata 1998) were found. Whilst they were not eligible to be included in the review, again neither of these two papers considered or discussed risks of infection, despite one discussing different utensils for delivering milk. Given that milk delivered by any utensil, irrespective of whether it is a bottle, teat, spoon or cup, each require cleaning. The authors do not feel that conducting a trial on comparing different delivery utensils and infection rates is of benefit. Without any supporting evidence or discussion in any papers regarding cup feeding in developing countries, the authors are reluctant to discuss and draw conclusions regarding this outcome We have acknowledged in the text of the review under unreported outcomes, "that none of the following outcomes were reported in any of the included studies".
Rajiv B et al comment on methodological influences which the authors have no impact on, such as sample size calculation. The statement made by the authors in the review is based on the evidence available; inferences cannot be made about design and sample size estimation by the authors. At this point in time there is a lack of evidence of effect.
Rajiv B et al again comment on design and methodology. The authors disagree with the comments and are adamant conclusions can only be based on the evidence found to be included in the review.
It is not the role of authors of Cochrane reviews to hypothesise on potential causes for lack of compliance for any intervention.
Again, the authors have presented the data available from included studies.
In reference to the excluded paper of healthy term newborn infants; this study was excluded because the population studied were healthy, term infants that were able to fully breastfeed; with supplemental feeds being offered as maternal choice, not because these were infants who were unable to fully breastfeed. This review is addressing the issue of supplemental feeds in the population of infants (irrespective of gestation age) who are unable to fully breastfeed. The authors have the view that term infants who can be fully breastfed should not be offered supplemental feeds as per the Baby Friendly Hospital Initiative (WHO1998). In addition, there are reports in the literature that caution needs to be exercised when cup feeding term infants due to the different tongue action required from that of breastfeeding, and term infants may reject the breast.
In the majority of the articles reviewed, the authors of these papers made a comment about the difficulty of ensuring compliance with this intervention. This is often the reality of conducting clinical trials in clinical settings with clinical staff. In this case, the authors do not feel that it was a question of poorly designed clinical trials.
Based on the current literature and the evidence that was reviewed, the authors disagree with the closing comment and maintain their conclusion.
The authors look forward to updating this review should further randomised controlled trials be conducted.
In conclusion, if WHO have any unpublished data regarding term infants that are unable to fully breastfeed, we would be happy to include it in future updates of the review.
Gupta, A., Khanna, K., & Chattree, S. (1999). Cup Feeding: An Alternative to Bottle Feeding in a Neonatal Intensive Care Unit. Journal of Tropical Paediatrics, 45, P108-110.
Malhotra, N., Vishwambaran, L., Sunaram, K.R., & Narayanan, I. (1999). A controlled trial of methods of feeding in neonates. Early Human Dvelopment, 54, p. 29-38.
World Health Organisation, (1998). Evidence for the Ten Steps to successful breastfeeding. Division of Child Health and Development, World Health Organisation. 1998.