Most health care providers aren't trained to recognize victims of sex trafficking - and many don't realize that's a problem, according to a new study.

“The majority of medical providers will come across victims or patients who are at risk for victimization at some point,” said Angela Rabbitt of Children’s Hospital of Wisconsin’s Child Advocacy and Protection Services in Milwaukee.

OB/GYNs, emergency room personnel, doctors working with adolescents or with child abuse victims, and those working with urban and underserved populations are most likely to encounter victims of sex trafficking, Rabbitt said in an email to Reuters Health.

That’s because reproductive health care problems like pregnancy, abortions, and infection, and also violence related injuries are more common in these individuals, she said.

Rabbitt and her coauthors reached out to physicians, nurses, physician assistants, social workers, and patient and family advocates at several hospitals and medical clinics in Wisconsin. Of about 500 providers contacted, only 168 – mostly women - filled out the online surveys.

More than 60 percent said they’d never been trained to recognize a victim of sex trafficking. Those who did receive training were more likely to say that trafficking is a major problem locally and had more confidence in their ability to identify victims.

Only 10 percent of providers with training said they had never encountered a trafficking victim, compared to 35 percent of those without training.

The surveys included various vignettes designed to test whether providers would recognize a victim of sex trafficking, such as an underage female who is forced to have sex by an adult, or who chose to have sex for money.

In either case, a minor would meet the legal definition of sex trafficking victim, but only 48 percent of providers correctly identified this.

Lack of training and awareness are important barriers to identifying victims, the authors write in Pediatrics.

“It’s no surprise because where are people going to learn about this?” said Donna Sabella, director of the Office of Human Trafficking at Drexel University College of Nursing and Health Professions. “It’s typically not part of any medical school curriculum.”

Sabella said social work departments at some U.S. universities offer short courses to give health care providers an overview of what sex trafficking is and what its victims may look like - which is to say, Sabella said, that they could look like anyone.

Good data are lacking on how many people are victims of sex trafficking, but it’s well known that big sporting events like the Super Bowl draw traffickers in large numbers, Sabella told Reuters Health by phone.

“We can’t arrest people, we don’t interrogate people,” but there are helpful questions to ask, and clear steps to take when reporting a victim, she said.

Adult victims can decide for themselves if they want the crime reported, she said. But if a provider suspects a minor is a victim of trafficking, they’re mandated by law to report it.

“We recommend reporting to both law enforcement and child protective services,” Rabbitt said.

Many victims are unwilling to disclose their victimization and many are simply not asked, she said.

“It is clear that the number of victims is probably much higher than the current research would suggest and that the number increased significantly once we became aware of the problem and started screening patients,” she said.

It is especially important to look for signs of victimization among kids and young adults.

“I think often when the community, including the medical community, sees a victim of domestic sex trafficking their first thought is that he or she is a prostitute who chose that lifestyle,” Rabbitt said. “There is now a growing awareness that many “prostitutes” start out as children or as young adults who were coerced or forced into the sex trade and now due to fear, addiction, or many other reasons, find it very hard to get out of the life.”

“When you see them as victims, it makes it more obvious that we should be actively trying to recognize them and taking steps to keep children from entering the lifestyle in the first place,” she said.