how to get adjusted prevalence after svyglm in R?


suppose Y is a dichotomous outcome (1/0) from a survey data. I run a logistic regression on a few categorical variables like a,b,c,..

fit1<-svyglm(Y~a+b+c+d+e+a*b*c, design=data,nest=T)

how can I get the adjusted prevalences of Y on these independent variables including the interaction term?

Thanks so much!