The reasons for the small population growth before the 20th century?

The main reason for the small growth in the population until the beginning of the 20th century is the low standard of living of the majority of the population, constant epidemics, as well as almost incessant hostilities.

As a result of the fact that medicine was at a very low level, and in most large cities there were unsanitary conditions, the average life expectancy reached hardly 40-45 years.

The industry lacked security measures, people worked in very difficult conditions, as a result of which every day at work could be the last.