We did a weekend for pre-cana and I seem to remember “natural birth control” (aka the rhythm method with the addition of paying attention to signals of ovulation from the women) as one of the “classes”. It was actually a very good experience and not as heavily religious as I thought it would be.
I still remember the discussion with the priest about marriage and his asking about having kids (which we both wanted). I asked if someone would be barred from marriage if they knew they could not physically have kids. He said you had to be “open” to having kids, but did not get a full answer about the situation in which someone had been told they could not have children due to a physical or medical condition.