>> the law was first introduced in the Russian SFSR in 1920
Poland was never part of the Soviet Union. It became socialist and part of the eastern block only after WW2, so I doubt the legal abortion date.
Also I mean, yeah the eastern block was quite progressive in some ways, but human rights were not one of them. Some of the gain were hugely offset by the millions of people who were tortured and killed by the system. Also much more blood thirsty in the Soviet Union than in Communist Poland.