Editor's Note: As part of CNN.com's new Crime section, we are archiving some of the most interesting content from CourtTVNews.com. This story was first published in 2004.
(Court TV) -- Mark Hacking is accused of killing his pregnant wife, Lori, in Salt Lake City. Scott Peterson is accused of killing his pregnant wife, Laci, in Modesto, California. Meanwhile, as their cases play out before a national audience, countless other husbands and boyfriends stand accused of the same crime in courtrooms across the country.
Roger McBeath, 22, for example, is charged with murdering his pregnant girlfriend, 18-year-old Ashley Lyons, in Georgetown, Ky.
"People are interested in Laci Peterson and Lori Hacking because they seemed so normal and happy in their relationships. People wonder, 'Where is this coming from?'" said Dr. Diana Cheng, director of women's health at the Maryland Dept. of Health and Medical Hygiene.
"The reality is there are a lot more of these cases that either aren't reported in the news or we just don't know about," Cheng said.
In 2001, Cheng and Dr. Isabelle Horon conducted a study in Maryland to determine the leading cause of death among pregnant women from 1993 to 1998.
Of the 247 women who died while pregnant, homicide was found to be the leading cause of death, accounting for about 20 percent of the cases.
"Women tend to think pregnancy is a safety zone, especially if they are already in an abusive relationship," Cheng said. "But what we're seeing is that no woman is safe from domestic violence or its most severe consequences."
Fear of fatherhood
Though very few pregnant women actually become victims of homicide out of the 688 women murdered in Maryland over that five-year period, only 50 were pregnant such figures reveal a chilling trend.
As more statistics on pregnancy-related mortality become available, experts are beginning to see pregnancy as an aggravating factor that increases a woman's risk of being murdered.
"Pregnancy is obviously a big, life-changing event, especially for a man. The emotional and financial responsibilities involved are huge stones around their necks," said Pat Brown, a criminal profiler and president of the Sexual Homicide Exchange.
However, Brown said, if something happens to the wife and child, those responsibilities disappear.
"If he doesn't want the child, why doesn't he just leave her?" she said. "He can do that, but that doesn't eliminate the responsibilities: child support, alimony, then as they get older, the kids want to see you. It never ends."
Even though famous cases such as Peterson's and Hacking's show how husband's are often the chief suspects in their spouses' deaths, Brown said there are no hard statistics because such instances are difficult to prove.
"We already know that 42 percent of murdered women are killed by their intimate partners. What remains to be established is the link between spousal or intimate partner homicide and pregnancy," Brown said. "The rate of women being murdered by their husbands and boyfriends because of the pregnancy is a lot higher than the statistics could possibly prove."
Meaningful statistics about such murders, however, require facts that are often too hard to gather.
First, it must be proved that the pregnant woman was murdered, which usually requires a body and a cause of death.
Second, it must be proved that the woman was killed because she was pregnant, not just that she happened to be pregnant when she was murdered.
Most importantly, you need a conviction to substantiate a husband's or boyfriend's culpability.
Defining a death
Every state conducts annual studies of maternal mortality rates, usually distinguishing between pregnancy-related deaths medical complications arising from pregnancy and non-pregnancy associated deaths, such as motor-vehicle accidents or drive-by shootings, for example.
But the problem with these definitions is that they don't take into account socially related deaths such as homicides.
"This definition restricts the potential causal contribution of pregnancy to women's deaths, because only causes of death that are biologically related to pregnancy are counted," wrote Victoria Frye, editor of the Journal of American Medical Association.
Some studies, however, have taken the leap to examine homicides of pregnant women. Many come up with similar findings as Cheng's.
In 2002, the Wake Forest School of Medicine released its study on maternal deaths in North Carolina from 1993 to 1997. It concluded that "the number of homicide deaths [35 out of 297 deaths] exceeds the number of deaths from any one of the pregnancy-related conditions."
Nonetheless, in the same years, motor vehicle accidents and other nonmedical incidents topped the lists.
Though many of these studies are broken down by race and class, Dr. Judith McFarlane says intimate partner abuse and homicide is not a lower-class issue.
"A woman with more resources and money may have more options, but it doesn't make her any less of a target," said McFarlane, a professor at Texas Woman's University who conducted a study correlating abuse during pregnancy and homicide.
Her research found that domestic violence was the leading indicator for homicide among pregnant woman.
"We as a society don't hold men accountable for their violent actions," McFarlane said. "To prosecute someone through our courts often takes more time than the victims of domestic violence can afford to spend waiting for action to happen."
McFarlane said the recent passage of Laci and Connor's bill, which makes it a federal capital offense to murder a fetus, and the correlating publicity to Scott Peterson's murder trial helps send a clear message.
"Before, the legal waters were very murky when it came to the murder of an unborn child," she said. "Now the law is clear and the Peterson trial publicity makes the extent of that law very clear."
Brown said the bigger problem is that women often don't come forward until it is too late.
"Men who cross the line to murder their pregnant wives and girlfriends show signs of being psychopathic long before the murder," she said.
She added that women often rush into relationships out a desire for companionship and then choose to remain in them, even after it becomes obvious that the relationship is troubled, often "explaining away" less than honorable behavior for the same reasons.
"Women should be even more cautious about getting pregnant with any man who exhibits a lack of concern for her happiness and well being, is manipulative, is a pathological liar, exhibits grandiose thinking, and has a history of dishonesty." E-mail to a friend