RIO DE JANEIRO: When Estefanie Ferraz went to prison, she had been living as a woman for around a decade, had undergone more than half a dozen plastic surgeries including breast and cheek implants to enhance her feminine looks, and was saving up for a sex change operation.

But her identification card said she was a man.

The transgender 29-year-old was sent to a prison for men in Rio de Janeiro where, she says, she was stripped of her female name and shorn of her long locks and dignity.

Brazil's penitentiaries are notorious for rampant overcrowding and violence endured by all inmates. But advocates say few prisoners are as vulnerable as transvestites and transgender people, who are often singled out for taunting and physical and sexual abuse.

In Rio de Janeiro, new regulations aim to curb such abuse within the state's 52 penitentiaries. Advocates have hailed the rules that ban discrimination against Rio state's approximately 600 transgender prisoners and protect their gender identities while behind bars.

"In Brazil, even regular prisoners are an invisible to society at large. Transgender prisoners are doubly invisible . and vulnerable," said Claudio Nascimento, who heads the Rio Without Homophobia advocacy group, which lobbied for the new rules.

"There was a generalized lack of respect and acceptance" of transgender prisoners, said Col. Erir Ribeiro da Costa Filho, head of the Rio state prison agency. With the new regulations, "we're trying to bring dignified treatment into the system."

The rules adopted in late May allow transvestite and transgender inmates to be known by their common, rather than only their legal, names. They guarantee access to conjugal visits and let transgender people who identify as female to decide whether to serve their sentences in a women's facility. In the United States, federal standards mandate that decisions about whether to house transgender inmates in male or female facilities be made on an individual basis, depending in part on where they would be safest.

Rio's new rules also guarantee access to hormone therapy, which are available to inmates in some U.S. states, and allow transgender prisoners living as women to wear lingerie and makeup and keep their hair long. Transgender inmates are also spared humiliating strip searches in front of other prisoners and will no longer have to remove their shirts for sunbaths.

Usually a highlight of life for prisoners held in overcrowded cells, sunbaths were a nightmare for Ferraz. After shaving off her mane of curls, guards at one all-male facility forced her to remove her shirt in the courtyard, exposing her implanted breasts to hundreds of fellow prisoners.

"It was beyond horrible," said Ferraz, a former prostitute serving a 10-year sentence for the attempted murder of a man she says pulled a gun on her after soliciting sex. "Everyone was staring, cat-calling, screaming at me."

Rio's new measures were adopted amid an outcry over the brutal beating in April of a transgender woman at a detention center in neighboring Sao Paulo state. Police are investigating allegations that officers tortured Veronica Bolina after graphic photos of her went viral on social media. In images taken before her detention, Bolina is striking, with cat eyes, prominent cheekbones and flowing hair. After, she's all but unrecognizable, her hair roughly shorn, her face a puffy patchwork of lesions and her eyes swollen shut.

LGBT advocates say it's hard to measure the extent of such abuse against transvestite and transgender prisoners in Brazil because it often goes unreported. In Bolina's case, she initially blamed her wounds on fellow prisoners, apparently out of worries about possible police retaliation.

But experts agree that transgender prisoners worldwide are at much higher risk of abuse than other inmates — particularly sexual abuse.

"Transgender prisoners are one of the most vulnerable groups (for) sexual violence in detention," said Jesse Lerner-Kinglake, spokesman of the California-based nonprofit Just Detention International that supports efforts to stop prison rapes.

He cited a U.S. Justice Department report issued last year in which nearly 40 percent of transgender inmates surveyed reported being the victim of sexual violence over the prior year, as well as a 2007 report by California's prison authority that found transgender inmates are 13 times more likely to be victims of sexual assault than other prisoners.

In Brazil, advocates for lesbian, gay, bisexual and transgender people say the criminal factions that dominate prisons can actually help shield transgender inmates from sexual assault. Those groups typically ostracize transgender prisoners, requiring them to eat off separate dishes and avoid even accidental physical contact with the general population. Inmates found to have had sexual contact with transsexuals risk retaliations that can include lynching.

Still, the protection afforded by such discrimination only goes so far.

"When there's a prison riot, when the criminal factions that control the penitentiaries decide to mutiny, transgender inmates are always the first ones to be killed," said Rio de Janeiro Congressman Jean Wyllys, an LGBT rights crusader.

Danny Campos de Oliveira, serving an 18-month sentence for a larceny conviction, said the new rules have already improved prison life.

Before transgender prisoners were "bald and ugly, with beards because they couldn't use hormones," said Oliveira, whose hair shone with blond highlights. Now, they "come out of here with more dignity, a bit less marginalized."