The 34 included studies produced a total of 14
meta - analyses for
physical aspects of health measured at post-intervention (including weight, length, leg, arm, chest and head circumference, cortisol, sleep length; crying / fussing, bilirubin, incidence of illness); 18
meta - analyses of
aspects of mental health (parent - infant interactions; parenting stress; attachment) and development (infant temperament, psychomotor and mental development); and three
meta - analyses of weight, length and head circumference measured at follow - up.