Abstract
In March, 2001 The World Health Organization (WHO) convened an Expert Consultation to recommend to WHO an optimal duration of exclusive breastfeeding. WHO formulated the specific questions to be addressed, selected the membership for the meeting, prepared background documents, and provided the venue for the meeting. After the meeting WHO formally accepted the recommendations and began to implement them. The Consultation recommended that WHO change its recommendation on exclusive breastfeeding from four-to-six months to a recommendation to promote exclusive breastfeeding for six months. This recommendation was contingent upon WHO also accepting and implementing other recommendations to deal with possible detrimental side effects, and to support mothers who did not exclusively breastfeed for six months. The amount of scientific evidence available was more than is often available for policy decisions in health, but much less than desirable to address issues of generalizability across and within populations. The evidence for the contingent recommendations was also less than desirable and raises a number of important research questions that now need to be addressed.