Many stay in the city but move out to the burbs the moment they have a baby on the way (some stay in the city with kids of course, but few). The reason is both

Many stay in the city but move out to the burbs the moment they have a baby on the way (some stay in the city with kids of course, but few). The reason is both that it's kind of expected and that there's very few affordable apartments suitable for families with more than one kid. Other reasons like that the city is unsafe for children etc, is just a result of few families in the cities and bad urban planning.