Protests have been taking place in Polish cities for the third night in a row following the introduction of a near-total ban on abortion.
Abortion is now allowed only in cases of rape or incest or when the pregnancy threatens the life of the mother.
Demonstrators have defied coronavirus restrictions and freezing temperatures to protest after the judgement was enforced on Wednesday.
The majority of Poles opposed a stricter ban on abortion.
Protesters in Warsaw marched through the streets chanting "freedom, equality, abortion on demand", the BBC's Adam Easton reports from the capital.
Many carried banners, with slogans including "My government is killing me", "My body, my choice" and "The revolution has a uterus".
An October ruling by the Constitutional Court found that a 1993 law allowing abortion in cases of severe and irreversible foetal abnormalities was unconstitutional.
In 2019, 98% of abortions were carried out on those grounds, meaning that the ruling effectively banned the vast majority of pregnancy terminations.
The ruling provoked outrage from supporters of the right to abortion, fuelling protests that morphed into more general anti-government demonstrations.
Poland's conservative government, which has strong ties to the country's powerful Catholic Church, supports the ruling.
The court justified its ruling on the grounds that "an unborn child is a human being" and therefore it deserves protection under Poland's constitution which ensures the right to life.
There is anger over the way the ruling has been introduced, without a public or parliamentary debate and by a group of judges who are widely seen as loyal to the government.
Krzysztof Sobolewski, a senior official from the ruling PiS party, said the protests were illegal due to Covid-19 restrictions.
"People who organise these protests... should realise they are risking the lives of the participants and those close to them, because it threatens, God forbid, a new coronavirus wave," he told the state PAP news agency.