Daily sleep duration measured by actigraphy tended to be higher in the intervention children at three months ( mean difference 10.9 minutes , 95 % confidence interval -19.0 to 40.8 minutes , effect size 0.2 ) and six months ( 9.9 minutes , -16.3 to 36.1 minutes , effect size 0.3 ) ; however , this measure was only completed by a subset of children ( n = 54 at three months and n = 37 at six months ) .