Breast is best, and a new Cochrane review shows how expressing breast milk can be made easier. Not all babies are able to feed at the breast and some new mothers find that they need to express milk for their baby. A new Cochrane review has examined the evidence on different techniques and brings all this knowledge together in a single report.

The authors of the review searched for all randomised and quasi-randomised trials in which methods or techniques for expressing breast milk were compared for babies of any age. They were also willing to include crossover trials, in which different techniques would be tried by the same woman, providing that these began when the baby was at least 28 days old. This limit was set to allow adequate time for the mother’s milk supply to become properly established after birth.

Three crossover trials were found, with just over 100 women, of whom just under 100 could be included in the review. There were also nine of the more usual parallel group trials, in which the different techniques were compared between groups of women. These trials had recruited 514 women, but nearly 80 were not available for the review. And, when it came to the formal statistical analyses, the authors were even more limited by the reporting of the studies. They were left with just six of the 12 trials, and only 397 women.

The crossover trials were in healthy babies several weeks after birth; whereas the parallel trials were in preterm babies or sick babies receiving neonatal care. The typical comparison in the trials was between different types of breast pump. Sometimes this was compared with hand expression and, in some trials, simultaneous expression from both breasts was compared with one breast at a time. One trial, done in the USA in the 1980s, randomised half the women to listen to a 20-minute relaxation tape.

The review concludes that mothers achieved greater volumes of expressed milk over six days using the electric or foot pump, compared to hand expression. They also found that the relaxation tape increased the volume, when it was used in the second week of breastfeeding. Simultaneous pumping was found to take less time, than the sequential use of a pump. These findings come from about 30 years of research, in which only a tiny fraction of women expressing breast milk have had the opportunity to take part in research to identify the best method. Definitive answers will need definitive research. Furthermore, as well as measuring the performance of different pumps in terms of the volume and content of the breast milk, such research also needs to allow the women themselves to provide information on their feelings about the different methods.

This Cochrane review is available in full at www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD006170/frame.html

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October 27 2008