There are plenty of countries where birth is far more dangerous, and is a high gamble with your life. People still have unplanned kids.
So the evidence shows you are wrong. When it is hard to control fertility, people who are poor, impulsive, abused, and have their sexual knowledge controlled by religion, have more kids.
Organized people plan. Not everyone is organized, and from work experience, it’s useless to try to figure out how to fix their brains. Bigger consequences doesn’t create more thoughtful people. It just creates the results of those bigger consequences.
In the United States the places that have the highest percentage of prolife voters also have the most people unable to long term plan, including getting a high school education, holding down a permanent job, and not using drugs.