MadB it was one of the first things we learnt in our mid class. The topic was how research can contraindicate commonly held beliefs. Have a look at
Pacifier use versus no pacifier use in breastfeeding term infants for increasing duration of breastfeeding.
Jaafar SH Jahanfar S Angolkar M Ho JJ
Cochrane Database of Systematic Reviews, Mar 01, 2011, No. 3