I don’t know in general, but especially when moving from rural to more industrial/city based work, the incentive to reproduce is different. Traditionally, having children has been seen as beneficial in rural economies because the family is building its labor force, and the family works together as a unit to provide more stability overall. Wage labor in cities is more individualized and doesn’t require the family unit to achieve a singular goal together, so children begin to be viewed as a drain rather than a benefit.
I don’t know in general, but especially when moving from rural to more industrial/city based work, the incentive to reproduce is different. Traditionally, having children has been seen as beneficial in rural economies because the family is building its labor force, and the family works together as a unit to provide more stability overall. Wage labor in cities is more individualized and doesn’t require the family unit to achieve a singular goal together, so children begin to be viewed as a drain rather than a benefit.