to 36%, with 95% confidence and 80%power, 399 per group were required. To detect a 10% difference in the other direction (ie, 46–56%), 411 per group were required. Using the larger figure, 822 women were needed in total. We allowed for 18% loss to follow-up, and thus planned to recruit 1000 women. We aimed to recruit an equal population of primiparous
and multiparous women, given that local data showed no difference in the percentage breastfeeding at 6 months.