Se Cathedral, the seat of the archdiocese of Sao Paulo, on Saturday witnessed a peaceful protest, a pro-life initiative. About 4,000 people took to the streets to protest "against abortion and for life".
The crowd, estimated at 4,000 by local police, stood in silence for several hours in Cathedral Square in Brazil's largest city starting at 10:00 am (1300 GMT) while waving Brazilian flags and wearing t-shirts promoting their cause.
Abortion is illegal in Brazil except in cases of rape or if the woman's health is in danger.
But a million women still seek clandestine abortions in operations that kill thousands each year, according to officials.
The abortion debate reached a new high earlier this month when Brazilian archbishop Jose Cardoso Sobrinho excommunicated the mother and doctors of a nine-year-old girl who had an abortion after allegedly being raped by her stepfather.
The excommunication was promptly denounced by Brazilian President Luiz Inacio Lula da Silva and the National Conference of Bishops of Brazil (CNBB), which said the child's mother acted "under pressure from the doctors" and that the circumstances should be taken into consideration.
Rino Fisichella, president of the Pontifical Academy for Life at the Vatican criticized the excommunication, saying it was first "necessary and urgent to save the innocent life" of the girl.
But Cardinal Giovanni Battista Re, head of the Roman Catholic Church's Congregation for Bishops, defended the excommunication and said the twins the girl had been carrying had a right to live.