Although most of the included studies used the WHO
definition of exclusive breastfeeding (3), few clearly indicated the timeframe within which exclusive breastfeeding was assessed.
(It's the same as researchers» insistence, nowadays, on a clear
definition of «
exclusive breastfeeding»; it's only since the importance
of this has been appreciated that the real differences between
breastfeeding and formula feeding have begun to emerge.)
However, the organization also called for more research regarding the benefits
of 6 vs 4 months
of exclusive breastfeeding.25 Thus far, several studies in industrialized countries revealed that a shorter duration
of breastfeeding increases the risk
of common infectious diseases, such as respiratory and gastrointestinal tract infections.8, 19,24,26, — , 32 However, in these studies, various
definitions of the exclusiveness
of breastfeeding were used24, 27,28,30 or the combination
of duration and exclusiveness
of breastfeeding was not taken into account.8, 31