CURITIBA, Brazil (AP) _ For most of her 23 years, Dalva da Silva clung to the hope that she, her mother and three sisters would break the grip of poverty and escape the two- room hovel in a hillside slum outside Curitiba.

An unwanted pregnancy took the hope away. She had no husband, no schooling, no skills. Her life would be a series of low-wage jobs, her home always a slum.

Then Dalva learned that the baby might be her ticket out of poverty.

During a checkup at a maternity hospital, an off-duty nurse told her to turn the child over to an agency that matched infants with rich couples. The nurse said the baby was worth $1,000, as much as Dalva could earn in 18 months.

One night, Dalva wrapped 28-day-old Felipe in a sweater, slipped out of her house and took a bus to the Sao Carlos Hospital, where four members of a baby- smuggling ring waited in a station wagon.

They were to drive the boy 520 miles north to Rio de Janeiro, collect $30,000 from an Italian couple and put Felipe on a plane for Rome, but the plan went awry. An anonymous informant called federal police, who arrested Dalva and the baby smugglers. Felipe was taken to a child-care center.

The case attracted national attention to the shadowy network of lawyers, judges, doctors and nurses who sell infants to foreign couples for huge profits.

''It's a stinking business,'' said Joao Noronha, chief of the anti- kidnapping division of the federal police in Curitiba, capital of Parana, one of the states where baby-trafficking is most common.

Noronha also indicted four other members of the ring involved with Dalva and Felipe, including Arlete Hilu, 47, the gang leader.

Police say Hilu, a Parana lawyer who illegally arranged at least 500 adoptions for Isreali couples, was arrested in 1988 for selling an infant girl to an Israeli couple in Paraguay for $10,000.

Hilu, released on probation in 1990, set up another baby-smuggling operation in four states of southern Brazil, police said, and sold more than 60 babies before she was arrested again.

Adoptions by foreigners are legal in Brazil, but arranging them for profit is punishable by up to four years in jail.

Each year, thousands of single mothers sell their babies to smugglers. The mother receives up to $3,000, or sometimes an apartment, a car, stereo equipment, even food.

In 1991, Ceara state police found that Maria Ferreira do Nascimento, 21, had traded her infant daughter for 6 pounds of rice, 6 pounds of beans and a sack of coffee.

Foreigners generally do not know paying fees to middlemen is illegal, said Jose Batista da Costa, a federal inspector in Curitiba.

Baby traffickers often tell adoptive parents local regulations require an ''honorarium'' of $10,000 to $15,000, when in fact, court fees and interpreters cost no more than $500 for a legal adoption.

Color is a big factor in the price of a baby. White-skinned, blue-eyed infants can fetch $50,000, but dark-skinned children never sell for more than $20,000, da Costa said.

Authorities are even investigating reports that Brazilian babies are sold abroad for their organs. That inquiry began after two Italian judges came to Brazil in 1990 to look into charges that babies were taken to Mexico and killed to supply organs for transplant in Italy.

Parana, Santa Catarina and Rio Grande do Sul states, all in the far south, are ''hunting grounds'' for baby gangs because of the many German, Russian, Polish and Italian immigrants who settled there, according to da Costa.

Smugglers sometimes send women into slums to pose as social workers seeking children for wealthy local families. They pay nurses and gynecologists to steer pregnant women to them.

Once a donor is found, traffickers can bribe officials and arrange the paperwork in two weeks. Red tape lengthens the legal adoptions process to about six months.

In 1990, federal police raided the home of two nurses in the poor coastal state of Pernambuco and found 12 infants awaiting sale to Italian couples.

A year later, police broke up what they called a ''baby-smuggling machine'' in Joao Pessoa, capital of Paraiba state. More than 200 people were arrested, including lawyers and court clerks.

Despite the police activity, the baby-export business appears to be growing.

Numbers are uncertain, but federal police say about 1,500 Brazilian babies were illegally adopted by American, Israeli, Canadian, West German, French and Italian couples in 1982-1986.

In 1990, officials estimate, there were about 1,000 clandestine adoptions in Brazil. By 1992, the number had risen to at least 3,000, according to a federal police report to a congressional investigative panel in March.

A report in the same month by Interpol, the international police agency, said about 1,500 babies from Paraiba state had been sold abroad since 1986 at an average price of $30,000.

''It's not enough to punish traffickers,'' said Dr. Jose Raimundo da Silva Lippi, president of the Brazilian Association for the Prevention of Infant Abuse. ''We need to streamline the adoption process to deter this kind of thing.''

Police say Brazilian baby traffickers now appear to be operating in Paraguay and Uruguay.

On Oct. 6, police caught a Paraguayan woman and Brazilian tour operator at the Rio airport, preparing to fly to Israel with a 4-month-old girl who had been undernourished when they bought her from a poor Paraguayan family. Police said they had fattened her quickly with proteins and vitamins.

''The worst part is, they treated the girl like cattle,'' said Edson Antonio Oliveira, chief of Interpol in Brazil.