To evaluate this intervention, a two arm, single group, superiority, multicentre, cluster randomised controlled trial with a nested observational study will be conducted at 26 pharmacies in Lusaka, Zambia. A randomised trial design will be used to assess the effectiveness of the pharmacy-based intervention in increasing use of the call centre. As it is not possible to randomly assign women to actually use the call centre and use will be largely based on self-selection, the nested observational study will then compare the experience of women who use and do not use the call centre.