Much like the church of England has everything to do with what goes on here
I think you'll find the reasons behind having big families is in the hope at least one of them can get them out the mess the previous generation found themselves born in. ..not to mention being cared for in later life. ..Unfortunately that's the crux of it.
You'll also find a lot of the girls don't like doing or taking any form of contraception. ..my wife's idea of contraception was to have no sexual intercourse at all. ..job done.
The Catholic Church may hold some power in Government but on the street. ..In my experience, the folks do as they please