In the cited context, wherever is an "emphatic" alternative to where. But a "stylistic choice" like that is unusual in the context of legal texts, so at least some readers will try to come up with a reason for the unusual choice. Personally, if I saw wherever in this context, my first guess would be that it's from a fake news source trying to promote a non-existent law.
Do the words 'Where' and 'Wherever' mean the same in this sentence?
The popular question words how, when, what, why, which and some more all have their accompanying word ending in -ever, like however and whatever. It seems to me that the word wherever is somewhat
orthography - Why is it "wherever" instead of "whereever"? - English ...
Apologies for the title which sounds like the Shakira classic, but would you say "Thank you for providing help whenever possible" or "wherever possible"
None is ungrammatical; few would use the unabbreviated forms; 'whenever' and especially 'wherever' would probably be a lot more idiomatic. The variants starting 'wherever' etc would probably be more usually used.
Open for “anyone”? Or open for “everyone”? Difference between “anyone” and “everyone”? What is the difference between “anyone” and “everyone” in this context This previous question may also be of interest (although it doesn't discuss the word anywhere): His camera accompanied him everywhere/wherever he went in the world.
Whoever else Whatever else Whenever else Wherever else Why ever else (Note: Whyever used to be an accepted spelling, but it has mostly died off.) However else In your example sentence, it would work fine with a slight reordering: Fertility might have fallen among women born between 1940 and 1960, and whenever else remained unchanged.