All Eastern European married women shaved all their hair until around 1840 when the Russian government declared it illegal. Most Chassidim were Moser Nefesh to maintain this minhag and Litvishe abandoned it. (My wife doesn’t do it even though we are Chassidish.)
Although we don’t know the origin exactly (there are various theories), it probably has to do with Chatzitza since it is only for married women.
This minhag is mentioned in the Takkanos of the Vaad Arba Arotzos (an umbrella group of every kehilla in Poland, Lithuania and parts of Ukraine and Belarus) almost four hundred years ago.