SEATTLE, Aug. 7 (UPI) -- A history of psychiatric disorders or substance abuse is a strong predictor of post-partum suicide attempts, U.S. researchers said.

Lead investigator Katherine A. Comtois of the Harborview Injury Prevention and Research Center and the University of Washington School of Medicine said maternal suicide after giving birth is relatively rare, but suicide attempts often have long-lasting effects on the family and the infant.

The researchers used the hospitalization and birth records from Washington state from 1992 to 2001 and found that 335 women had been hospitalized for suicide attempts. Another 1,420 women who had given birth but had not been hospitalized for a suicide attempt served as a control group.

The study, published in the American Journal of Obstetrics & Gynecology, found after adjusting for fetal or infant death and other variables, women who had been previously hospitalized for psychiatric disorders were more than 27 times as likely to attempt suicide as women without this medical history. Women with a history of substance abuse were six times as likely to attempt suicide, while psychiatric hospitalization and substance abuse together increased the risk by 11 times, the study said.