What was one cause of the population spike during the industrial revolution

Normally, during the agricultural revolution before there would be a population spike because children were valued for farm labor and there was a decline during the industrial revolution because children were not valued in the work force like in factories and cost lots more money to take care of.

However, if there was a spike in the population during the industrial revolution it would probably be because people had more kids to go out and work in the family business or go out and work in the factories which mean they were valued in the work force...

If u can translate that to english i will surely you!