In Warsaw, protesters caused traffic to grind to a halt on Jerozolimskie Avenue and Marszałkowska street, both busy thoroughfares running through the heart of the capital.
In defiance of rules that ban large gatherings amid a coronavirus epidemic, demonstrators brandished banners reading “Hell for women,” “This is war” and “Women's strike.”
Protests were also held in cities including Poznań in the west, Lublin in the east, and Kraków and Katowice in the south.
It was the fifth straight day of demonstrations against a court ruling which signalled a tightening of Poland’s abortion laws, already among the toughest in the European Union.
The street protests were sparked by a decision on Thursday by the country’s Constitutional Tribunal that abortion of a malformed foetus violates the constitution.
Gatherings of more than five people are forbidden in Poland under new rules aiming to limit the spread of the coronavirus epidemic that came into force on Saturday.
Officials on Monday reported 10,241 new coronavirus infections and 45 more deaths, bringing the total number of cases in Poland to 263,929 and fatalities to 4,483.