Study design and sample size determination

A descriptive cross-sectional study was conducted among currently breastfeeding mothers who were 18 years of age and older, having a child 12 months old or younger, receiving care for them and/or their child at the designated healthcare facilities and who consented to take part in the study. The age span of study participants was 18-49 years. Type of care received by breastfeeding mothers and their children include preventive care practices such as childhood vaccination, nutrition, counselling on danger signs and home care. Breastfeeding mothers and their children also received care for conditions such as malaria, respiratory infections and gynaecological infections. We excluded women from this study if they were chronically ill. The study period was between August and October 2016. The sample size for this study was calculated using the formula for sample size determination for cross-sectional study n = Z²Pq/d². Where n is the required sample size, P is the estimated proportion of use of herbal medicine during lactation (0.599); taken from a similar study conducted in Western Australia [13]. q = 1-P is the probability of those not using herbs i.e. (1–0.599), Z = value of test statistics corresponding to 95% confidence interval (1.96) and d = degree of accuracy/standard error (0.05) which gives approximately 363 participants as the minimum sample size. We decided to recruit 400 to assuming 10% non-response rate.