Sample size calculation
The study was designed to have power to detect clinically relevant differences in women’s overall ratings of ANC and a difference in means on the EPDS. The initial sample size calculation of 70 women in each group (with 80% power and an alpha of 20%) was based on a national population study on Swedish-speaking women’s satisfaction with ANC 2 months post partum.To have similar power to detect differences in EPDS mean scores, 63 women were required in each group, based on a hypothesised reduction from a mean of 8.0 in the control group to that of 6.0 in the intervention group.