The mean maternal EPDS scores at 26 weeks after delivery were 5.4 ( SD 4.5 ) in the twin intervention ( TI ) group and 6.9 ( SD 5.5 ) in the twin control ( TC ) group , and the mean difference between the groups was 1.5 ( 95 % confidence interval , 95 % CI , -0.2 to 3.3 ) .