The recent killing of 26-year-old Jessie Davis, who was nine months pregnant, has highlighted what some believe is a terrifying phenomenon.
According to a number of studies, homicide is one of the leading causes of death for pregnant women in the United States. Studies in Maryland, New York and Chicago determined that about 20 percent of women who die during pregnancy are murder victims.
Some states do not even keep track of the number of a pregnant women killed by boyfriends or husband. But the Washington Post identified more than 1,300 during a 14-year period ending in 2004.
Several high-profile examples exist. Take the case of Lori Hacking, who was pregnant with her first child when she was killed just after telling her husband, Mark, about the pregnancy. Mark Hacking eventually pleaded guilty to murdering her, admitting that he left her body in the Salt Lake City dump.
Then there is Laci Peterson, the California woman who was murdered on Christmas Eve when she was eight months pregnant. Husband Scott was later convicted of her murder.
Some question why men don't leave their wives and girlfriends rather than murdering them.
"Men who kill their pregnant wives are always psychopaths," said criminal profiler Pat Brown. "'She's in the way. I made a mistake and I think I will erase my mistake.' So, he kills her and he thinks that will solve the problem."
Brown believes if Bobby Cutts Jr., who denies killing Davis, his mistress, is the murderer as charged, then he fits the profile of a psychopath who shows little emotion about the victim.
Brown pointed to Cutts' lone media interview, when he told a local newspaper how hard the investigation had been on him.
"I haven't been myself," Cutts said in the interview. "I can't sleep. I can't eat. This is like the worst. I can't even imagine. I mean, this is like a movie."
While Laci Peterson was still missing, Scott Peterson told Diane Sawyer how difficult it was on him to walk the family dog.
"A lot of times, I can't make it very far," he said at the time. "I make it part of the way. I certainly can't make it to the part of the park where currently there's a big poster of her up."
Brown said these types of men never show much interest in their wives or their unborn children.
"They are only complaining about themselves," she said.
The No. 1 risk of death for pregnant women is the normal medical complication of childbearing, followed by traffic accidents and then homicide.
Police often look at spouses as possible suspects right away, and many of these murders are sudden outbursts of violence.
Stacy Phillips, a criminal defense attorney specializing in domestic violence, said the pressure of new responsibilities, like a new child, can and does erupt into uncontrollable emotions.
"When there's a relationship and a tension between two people, when money's at stake, bad things happen," Phillips said.