This review has been processed through the Cochrane Pregnancy and Childbirth Group although its subject matter falls outside the scope of the Group. The Group's scope does include the initiation of breastfeeding, but not the timing of its cessation. However, the topic is clearly of global importance and because it did not readily fit within the scope of any Cochrane review group, the Pregnancy and Childbirth Group was happy to assist with publication. This review was based on a systematic review by M Kramer, that was commissioned by the World Health Organization (WHO). The WHO review was very extensively peer reviewed by experts in review methodology and statistics, and in infant nutrition and lactation, including experts that the Review Group would have approached for our own refereeing purposes. We have therefore not sought an initial protocol, nor subjected the Cochrane review to further peer review of this type. The review has, however, been reviewed by the Consumer Panel of the Pregnancy and Childbirth Group.

There are other unusual features of this review:

1. Its title does not fit with the standard Cochrane format but we have been unable to construct a satisfactory title that does, whilst doing justice to the scope of the topic.

2. It includes data from studies in addition to randomized trials.

3. Maintenance and updating will be the sole responsibility of the contact author as the search strategy of our Review Group does not extend to this topic.

Jim Neilson
Co‐ordinating Editor
Cochrane Pregnancy and Childbirth Group