Losing a child dramatically increases a mother's risk of an early death, according to new research.

Researchers found that there was a 133 percent increase in the risk of a mother dying within the first two years of the death of a son or daughter.

Researchers Javier Espinosa of the Rochester Institute of Technology and William Evans at the University of Notre Dame studied 69,224 mothers aged 20 to 50 years for nine years, and tracked the mortality of children even after they had left home.

The study published in the journal of Economics and Human Biology, which is the first of its kind, revealed that mortality risk for mothers was greatest within the first two years following the death of a child, regardless of the child's age at the time of death.

Researchers also found that there appeared to be no difference in results even after accounting for the mother's education or marital status, family size, the child's cause of death or the gender of the child.

Researchers said that while there were not enough cases to make definitive conclusions about the cause of maternal deaths, they said that their findings were based on the National Longitudinal Mortality Survey, a nationally representative U.S. data source.

About 84 percent of the women studied were married, slightly more than half were between the ages of 20 and 34 and around a half had a high school education while a third had some college education or a college degree.

Although the is the first study to examine maternal mortality after the death of a child, earlier research from Denmark found that parents who experienced the death of a child had a higher risk of first-time hospitalization for a psychiatric disorder than parents who did not lose a child.

Danish researchers also found that mothers also had a higher risk of being hospitalized than fathers, and that the effect was most severe during the first year and significantly elevated for five years or more.