Author contributions
The present research was part of a larger study (PROCAS2) that was conceived, designed and led by DGE and DPF, with input from FH and several others who acquired funding. FH provided PPI input to all elements of the larger study, with further input from women who might use the system being elicited by LMcW, VW, and HR. The research reported here was designed and led by DPF with input from DGE. Project planning and administration was conducted by LMcW, SB, HR, AH and VW. Data curation was provided by SB, LMcW and AH. Data analysis was conducted by DPF. The present article was drafted by DPF, partly based on previous documents prepared by DPF, DGE and VW. DPF is responsible as a guarantor for the overall content. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.