Chile's socialist president Michelle Bachelet on Thursday signed into law landmark legislation to decriminalize abortion in certain cases, ending a strict ban in effect for decades.
Parliament passed the bill last month after more than two years of wrangling and a constitutional court challenge brought by conservatives opposed to the reform.
"We, the women of Chile, have conquered or regained a basic right, that of being able to decide for ourselves when faced with extreme cases" Bachelet, a pediatrician by training, told an audience of about 1,500, most of them women, at the signing event at La Moneda presidential palace.
The law will allow abortion in cases of rape, threat to the mother's life or deadly birth defects.
Opponents say the law violates the fetus's right to life, as enshrined in the constitution.
The law, which polls show has 70 percent support among Chileans, marks a major change in the once-conservative country, one of the last developed countries to recognize divorce, in 2004.
Abortion under any circumstances was strictly outlawed in Chile in 1989, during the final days of the Augusto Pinochet dictatorship.
For more than 50 years before that, abortion was permitted if the mother's life was in danger or if the fetus was not viable.
Bachelet has focused on a series of social reforms in the latter half of her second term, which ends next March.
Last month, Bachelet introduced a bill to legalize same-sex marriage and open the door for adoption by same-sex couples.