San Francisco, Jul 23 (IANS): Babies have an increased likelihood of being born prematurely if either their father or mother has a history of psychiatric diagnosis, a new study has shown.

According to the study published in the online journal PLOS Medicine, infants whose father or mother has a psychiatric condition have a higher chance of preterm birth than those whose parents do not, and the risk is even higher when both parents have such diagnoses.

Preterm birth has been linked to unfavourable health outcomes for newborns.

Women with psychiatric diagnosis have long been known to be at a higher risk of preterm delivery, but little is known regarding the danger in children of psychiatrically diagnosed fathers and couples with both parents having psychiatric illnesses.

The researchers analysed data on all live births to Nordic parents (parents who were born in Sweden, Finland, Norway, Denmark and Iceland) in Sweden between 1997 and 2016.

The researchers noticed an earlier gestational age in the offspring of parents with psychiatric illnesses.

About 5.8 per cent of babies were born prematurely to parents who did not have a diagnosis.

A paternal diagnosis increased the number of births to 6.3 per cent, while a mother diagnosis increased the number of births to 7.3 per cent. Preterm births occurred in 8.3 per cent of cases where both parents had a diagnosis, according to the study.

"Preterm birth can result in significant lifelong complications for the infant, and in my clinical experience, the mother has traditionally been held responsible for the events," said Michael Silverman, PhD, Associate Professor of Psychiatry at Icahn Mount Sinai and an author on the paper.

The researchers also found that the risk was further increased for offspring of parents -- mothers as well as fathers -- who had several co-existing psychiatric disorders.

"This new work demonstrates that the non-gestational biologic parent's (the father's) psychiatric history is also associated with the increased likelihood of obstetric outcomes traditionally attributed solely to the mother," Silverman said.

The researchers mentioned that children of parents with mental illness are at increased risk of being born too early and our study shows that both the mothers and fathers are important.