[iguy]

poor are not educated enough about reproduction to prevent childbirth

Many people say this. But it's worth knowing that, historically, lots of societies firmly limited reproduction when they were as poor as (say) most of Africa is now. The methods varied.

[letslightafire]

I can only think of China as an example of purposely limiting reproduction, what others are there?

[iguy]

Right, 20th century China is the example of government limiting reproduction which springs to mind.

What I had in mind was people limiting their own. In the west the main mechanism was delayed marriage (i.e. saving up a socially approved amount of money first) which kept us well away from starvation 500 years ago. In china/japan I believe the pattern was more infanticide (in the same period) but know less about this.