I first read it long before I'd even considered the possibility that books might be that upsetting!

It's less the use of the idea of falling birthrates as a tool for social control, and more that even in the pre-Gilead society there's a recognition of fertility crisis, and a suggestion that that was a looming demographic problem readers would be aware of at the time when the book was written, whereas now I think overpopulation seems like more of a worry.