Statistical analysis
The socio-demographic variables and the psychometric scales were compared between the three website use groups by ANOVA (continuously valued variables) or chi-squared tests (categorically valued variables).The relative importance of the factors listed in Fig. Relative importance analysisTo assess the direction and magnitude of the influences of the various factors were assessed by adjusted odds-ratios (AOR) from multinomial generalized linear mixed modelling (GLMM). The women are clustered within practices and therefore might be more similar to each other than to those across practices: GLMM accounts for this through a practice random effect. If the women are very similar within practices, ignoring the clustering and claiming they are independent will artificially and erroneously increase the power of the inference; this is particularly true for the practice characteristics that by construction are the same within practice.In all analyses, non-users were the reference category. Our null hypothesis was that there would be no difference in the characteristics of the women in terms of intervention usage.The intraclass correlation coefficient (ICC) indicates the proportion of the total variance explained by the grouping structure in the population [All statistical analysis was performed using R (version 4.1.2; R Core Team, 2022).