"It is true that we should depend on God's providence; it is also true that married couples are called to be generous in raising their children without arbitrarily limit-ing their family size to one or two children because of a desire to maintain a certain ‘standard of living.' Yet, the Church teaches that the gift of self in conjugal union is a human act, which means that it involves the use of our reason. Paul VI teaches that "the Church is the first to praise and recommend the intervention of intelligence in a function which so closely associates the rational creature with His Creator; but she affirms that this must be done with respect for the order established by God."
January 1, 1970
https://en.wikiquote.org/wiki/Christian_views_on_birth_control