Sample size
We estimated the required number of mothers/couples needed as follows: (i) we aimed to be able to demonstrate a 20% difference-in-difference (D-I-D) in mean VH scores between the two groups (i.e. at least 30% reduction in the MI group and 10% reduction in the control group at two points in time: just after the MI or leaflet distribution and at follow-up); (ii) expected 20% loss-to-follow-up rate at follow-up, based on previous interventions [