That doesn't appear to be true. Birth rates plummeted in the 60s and 70s[1], which is when women started to really join the work force in quantity.
Perhaps the people inclined to down vote think I'm advocating for banning women from work? Please realize I'm saying no such thing, I'm simply pointing out an obvious consequence for long term labor supply that simple reasoning can deduce and the data bears out.
The decrease in births is twice the decrease in infant mortality according to the sources we both linked. Also, it takes at least a generation before lowering infant mortality lowers birth rates. It does look like lowered infant mortality contributed quite a bit to the baby boom.
Perhaps the people inclined to down vote think I'm advocating for banning women from work? Please realize I'm saying no such thing, I'm simply pointing out an obvious consequence for long term labor supply that simple reasoning can deduce and the data bears out.
[1]http://www.pewresearch.org/fact-tank/2018/01/18/is-u-s-ferti...