I was induced at 36 weeks so perhaps mine may have changed later, but the closest I had appointments was 3 weeks. They were every 4 weeks even near the end of pregnancy as my control was very good.
Having said that, I saw my local midwife every 4 weeks and that increased to every two weeks after 28 weeks.
I can't remember exactly with my previous pregnancies but I think it went up to every two weeks at around 30ish weeks but that was because they had a worry about the amniotic fluid.