[Kangaroo-Mother Care: scientific evidence and impact on breastfeeding]

To describe the history of the Kangaroo Mother Care and present scientific evidence about benefits of this practice on morbidity and mortality, psychological and neurological development and breastfeeding of low birth weight infants.

Papers about Kangaroo Mother Care published from 1983 to 2004 were consulted, selected in Medline and Lilacs, as well as books, thesis and technical publications from the Brazilian Health Department.

Since its first description, Kangaroo Mother Care has been extensively studied. The analysis of randomized trials showed that it consists in a protection factor to breastfeeding at discharge (relative risk 0.41, 95% confidence interval 0.25 to 0.68). The method was always associated with the following reduced risks: nosocomial infection at 41 weeks' corrected gestational age (relative risk 0.49, 95% confidence interval 0.25 to 0.93), severe illness (relative risk 0.30, 95% confidence interval 0.14 to 0.67), lower respiratory tract disease at 6 months (relative risk 0.37, 95% confidence interval 0.15 to 0.89) and better gain of weight per day (weighted mean difference 3.6 g/day, 95% confidence interval 0.8 to 6.4). Psychomotor development at 12 months' corrected age was similar in the two groups. There was no evidence of a difference in infant's mortality.

A positive impact of Kangaroo Mother Care on breastfeeding was found. Although the method appears to reduce severe infant morbidity without any serious deleterious effect reported, there is still insufficient evidence to recommend its routine use. It is necessary to develop studies about effectiveness, acceptability and applicability of the method in the Brazilian context.