New mothers who deal with postpartum psychiatric disorders are more likely to commit suicide when compared to mothers who are not afflicted by these mental health disorders, a new study said.

For this study, an international team of researchers from Denmark, the Netherlands and the United States analyzed data on 1,545,857 Danish women that were collected from 1970 to 2011. The researchers focused on women who were dealing with their first onset of postpartum psychiatric disorders, which would manifest within the first three months after childbirth.

The team found that mothers who had postpartum psychiatric disorders were four times more likely to die due to natural or unnatural causes during the follow-up period in comparison to new mothers who did not have any mental health problems. Overall, out of the 2,699 women who were diagnosed with a postpartum psychiatric disorder, 96 had died.

Natural causes of death were defined as diseases and other medical conditions. Unnatural causes included suicides, homicides and accidents. The researchers noted that suicide risk for mothers with postpartum psychiatric disorders was significantly higher within the first 12 months after childbirth.

"The first year after diagnosis represents a time of particularly high relative risk for suicide in this vulnerable group," the authors wrote.

The researchers also found that the death rates were very similar for new mothers with postpartum psychiatric disorders and women with mental health issues that were not related to childbirth. The team noted that childless women with mental health issues still had the highest rate of death.

"The suicide cases are very rare, but when they do happen, they are of course extremely tragic. And it's not what people expect. The general belief is that a new mother doesn't take her own life, and that she ought to be enjoying motherhood, but the reality isn't always like that," Trine Munk-Olsen, a senior researcher at the Department of Economics at Aarhus BSS in Denmark, said in a press release. "We think it's important that women with postpartum psychiatric disorders are properly diagnosed and get the treatment they need, which possibly can prevent that they commit suicide."

The study was published in the American Journal of Psychiatry.