Thousands of protesters gathered in Warsaw to demonstrate a ruling that meant Poland has a near-total ban on abortion.
A decision last week by the country's constitutional court banned virtually all abortions, sparking a week of protests.
It ruled that abortions due to birth defects, which make up a majority of all legal terminations in Poland, are unconstitutional.
The country's laws on abortion were already some of the strictest in Europe.
Hundreds of thousands have been pouring into the streets for days, defying the risk of contagion amid a spike in COVID-19 infections.
The latest large-scale march is planned for Friday evening in Warsaw, the country's capital, in defiance of government appeals that people stay at home due to the coronavirus.
Poland has been hitting new records each day in terms of new reported cases of the virus, reaching nearly 22,000 on Friday.
The national public prosecutor has vowed to file criminal charges against organisers of the protests for “causing an epidemiological threat", a charge that could carry a prison sentence of up to eight years.
Klementyna Suchanow, one of the key organisers with the initiative Women's Strike, said she and many others refused to be deterred by either the virus or the authorities because they believe they are fighting for a fundamental right.
“This is about the freedom and dignity of people,” Suchanow said. "The will of people to protest should be a lesson for anyone who wants to impose authoritarian ways.”
Education Minister Przemyslaw Czarnek also threatened to cut off funds to universities that have supported the protests. Some cancelled classes during a nationwide strike on Wednesday.
Poland's president, Andrzej Duda, on Thursday appeared to have broken ranks with the government and backed demonstrators, saying he thinks women should have the right to abortion in some cases.
Poland is a largely conservative country compared to much of Europe, a place where churches fill up on Sundays and Roman Catholicism is deeply interwoven with the national identity.
The country's abortion law, which was forged in 1993 between the political and Catholic church leaders of the time, allowed abortion only in the cases of fetal defects, risk to the woman’s health and crimes — incest or rape.
The law has been often described as a “compromise” between those seeking liberal abortion regulations and the church, which favours a total ban.
However, no side has ever been satisfied with the 1993 law, and women's groups demanding greater reproductive rights say it is no compromise at all.
Earlier attempts by the conservative ruling party to change the law to ban all abortions were met with enormous street protests, including in 2016 and 2017.