London: Babies who are born prematurely may have an increased risk of a range of mental health problems, researchers have revealed.
Bipolar disorder, depression and psychosis were all more likely, the study in The Archives of General Psychiatry suggested.
Full-term pregnancies last for around 40 weeks, but one in 13 babies are born prematurely, before 36 weeks.
Researchers at the Institute of Psychiatry at King’s College London and the Karolinska Institute in Sweden analysed data from 1.3m people born in Sweden between 1973 and 1985.
They found 10,523 people were admitted to hospital with psychiatric disorders, and 580 of those had been born prematurely.
The academics showed full-term children had a two in 1,000 chance of being admitted. The risk was four in 1,000 for premature babies born before 36 weeks and six in 1,000 for those born before 32 weeks.
Very premature babies were more than seven times more like to have bipolar disorder and nearly three times as likely to have depression.
One of the researchers, Dr Chiara Nosarti, said the real figures might be higher as milder conditions would not have needed a hospital visit.
However, she cautioned that the risk was low and the vast majority of premature babies are perfectly healthy.
“I don’t think parents should be worried, but we know that preterm birth confers an increased vulnerability to a variety of psychiatric conditions and perhaps parents should be aware of this and monitor early signs of later more serious problems,” she told the BBC.
She speculates that “disrupted development” may affect the babies’ brains.