While there are certainly some countries that have guaranteed maternity leave, and are struggling, there does not seem to be any correlation between the two:
- Germany has 14 weeks at 100%, and 156 weeks at 67% to be shared between the parents, a 4.5% unemployment rate, and is considered to be doing far better economically that the USA.
- Norway has more than 35 weeks at at least 80%, a 4.1% unemployment rate, and is doing ok.
- Even dipping into less-well-off countries it is hard to find what you are talking about: Brazil has an unemployment rate of 7.9% and 17 weeks at 100%.
Germany was a ringer, but I chose the other two at random, looking for countries that could be having problems here. But given that the U.S. is nearly alone in the developed world for countries that do not have guaranteed maternity benefits, it is hard to find meaningful evidence for your point.
I hate it when people try to use their ideology as a substitute for facts.