Expectant mothers are more likely to die from murder or suicide than several of the most common pregnancy-related medical problems, U.S. researchers have found.

Roughly half of those women who died violently had had some sort of conflict with their current or former partners leading up to the death, causing experts to call for more thorough screening and follow up for domestic problems during pregnancy check-ups.

"I think that there's still an under-appreciation of the risk (for murder and suicide) and probably less screening than should be done," said Dr. Linda Chambliss, director of maternal fetal medicine at St. Joseph's Hospital and Medical Center in Phoenix, who did not participate in the new work.

The study shows that about three out of every 100,000 women who are pregnant or have a child less than one year old are murdered, and two out of every 100,000 kill themselves.

Those numbers remained fairly constant from 2003 to 2007, the years that the researchers examined.

They pulled their data from the Centers for Disease Control and Prevention's National Violent Death Reporting System, which includes 17 states.

Murder and suicide were more common causes of death than medical conditions related to the pregnancy, according to a different set of data.

For instance, fewer than two out of every 100,000 women died from either pregnancy-related bleeding, improper development of the placenta, or preeclampsia, a complication of high blood pressure that can occur during pregnancy.

Dr. Christie Palladino, the lead author of the study, told Reuters Health that deaths from medical problems during pregnancy have dropped in recent decades.

"We've seen improvements in the more traditional causes of death, likely due to advances in medical care and public health practices. But the rate of injury seems to remain constant," said Palladino, an obstetrician-gynecologist at Georgia Health Sciences University in Augusta.

This finding is especially troubling, she said, because violent deaths can be stopped.

"Even if the numbers are relatively small, you're talking about something that's preventable. It doesn't have to be there at all," agreed Chambliss.

Some groups of women were at a greater risk of violent death.

Women who died by suicide, for example, were more likely to be white or Native American, unmarried and over 40. Older women and those under 24 were at greater risk of being murdered, as were African Americans and unmarried women.

Palladino said her study, published in the journal Obstetrics & Gynecology, likely underestimated the number of violent deaths among pregnant women.

The National Violent Death Reporting System includes all records of violent deaths in the participating states, but in some cases the pregnancy status of the victim was unknown, and Palladino and her colleagues excluded those records from the study.

Palladino said pregnancy is a prime opportunity for working to prevent suicides and murders, particularly those related to domestic violence, because women regularly see health care providers.

"We want to make sure we intervene before we get to these really disastrous consequences," she said.