Vasectomy is a popular form of contraception among males that already have two children. We have been amazed at the number of men who take advantage of this free service.
Being a curious person, I have asked, over the past number of years, about birth control. It seems as though the most popular choice among females are the injectables, which are free. The pill is not free and is expensive.
The catholic church here is not a huge presence. There is one very small church and one small meeting place/church. That is it. We also have a number of other religions represented including Luz del Mondo and LDS.
All of my comments are based on my own knowledge and I live in the state of Guerrero. Other states and towns may be quite different.
Times change. People are becoming more educated, especially about life choices like the number of children they have and can afford.
Here is an interesting website with numbers: https://www.worldometers.info/world-population/mexico-population/