An analysis of jailhouse phone calls between men charged with felony domestic violence and their victims allowed researchers for the first time to see exactly what triggered episodes of violent abuse.

The findings showed that violence often immediately followed accusations of sexual infidelity made by one or both of the partners. Drug or alcohol use was often involved.

Researchers have long known that sexual jealousy played a general role in abuse, but this is the first time it was shown that it was a specific form of jealousy -- infidelity concerns -- that tended to initiate the violence, said Julianna Nemeth, lead author of the study and a doctoral student in public health at Ohio State University.

"What we were looking for was the immediate precursor -- what was the one thing that happened right before the violence that was the catalyst," Nemeth said.

"I have worked in domestic violence intervention for many years, but still the findings shocked me. We never knew that it was the accusation of infidelity that tended to trigger the violence."

The findings are powerful because they come directly from conversations of the couples involved in domestic violence, said Amy Bonomi, co-author of the study and associate professor of human development and family science at Ohio State.

"What we had before was what the abuser and victim said to police, to courts, to advocates, to health care providers," said Bonomi, who is also an affiliate with the Group Health Research Institute in Seattle.

"But we never before had the couple together discussing just among themselves what happened during the violent episode."

The study appears online in the Journal of Women's Health and will appear in a future print edition.

The study involved 17 heterosexual couples in which the male was in detention in a facility in the state of Washington for felony-level intimate partner violence. The victims had sustained serious injuries during the attacks, including severe head trauma requiring hospitalization, bite wounds, strangulation and lost pregnancy.

The researchers used up to four hours of recorded phone conversations between each couple.

The detention facility in the study routinely records conversations of detainees to increase jail safety. The couples were aware they were being recorded through an automated message at the beginning of each call. Such recordings have been approved by the state Supreme Court, and the researchers gained approval from the county prosecutor's office and detention facility to use the recordings. All the recordings involved cases that had already been resolved.

The researchers listened to the audiotaped recordings and wrote narrative summaries of couples describing acute triggers and chronic stressors for violence. Nemeth then created a table to summarize the themes found in the recordings.

The research team met weekly for two months to discuss the themes and develop a conceptual model to explain what they had found.

Along with the acute trigger for the violence, the researchers found a variety of other chronic stressors in the relationships of these couples that may have contributed to the abuse. One chronic stressor was the same issue that often triggered the violence.

"We found that long-term disputes regarding infidelity pervaded nearly every relationship," Nemeth said. "Even if it didn't trigger the violent event, it was an ongoing stressor in nearly all of the 17 couples we studied."

Drug and alcohol use was also a key both as a trigger to violence and a chronic problem. Alcohol or drugs helped escalate what started out as just a conversation into severe violence, she said.

Many of the couples discussed unmet mental health needs, and ongoing problems with depression and preoccupation with suicide.

Another key to understanding these violent relationships was the extent to which the couples had accepted traditional heterosexual gender roles, which were often justified through religion, Bonomi explained.

"We commonly heard the couples discuss how women are supposed to marry and have children, and how men are supposed to be strong and in control," Bonomi said. "Men tended to use these traditional gender role prescriptions to justify their use of violence."

The violence at times centered on "reproductive coercion" -- men who wanted to control when and if their partner became pregnant. For example, one man told his partner he was justified in raping her because she wanted to be a mother anyway.

Five of the 17 couples talked about severe violence during pregnancy and two women discussed a lost pregnancy as a result of violence.

In about half of the couples in which they had clearly internalized traditional gender roles, religion was used as a justification. In one case, the male abuser told his victim that his attack was about "cleansing your soul."

"It was very disturbing the way religion was used to justify the violence and to justify why the relationship should continue," Nemeth said.

These results should prompt several changes in procedures for victim advocates and other mental health providers, Nemeth said.

Advocates for domestic abuse victims often prepare safety plans to determine how much danger a woman may be in and what she can do to protect herself.

"A lot of safety plan tools don't ask specifically about sexual jealousy and infidelity, but it is a question we should be asking," Nemeth said. "If it is an issue that couples are discussing, it is a red flag that the relationship may be volatile."

The results also suggest there should be more coordination between health care providers helping those with drug and alcohol use, mental health issues, and domestic abuse, since all of these issues can be related.

"We need more coordination to help people on all different levels," Nemeth said.

Other authors of the study were Meghan Lee and Jennifer Ludwin, both graduate students at Ohio State.

The study was funded by the Criminal Justice Research Center at Ohio State and the Group Health Foundation of Seattle.