WHEN parents of very small premature infants are stressed or depressed, their children are more likely to develop behavioural problems by age 3, according to new research.

What’s more, the worse the parents scored on psychological well-being indicators, the more likely their youngsters were to develop the problems.

“The psychological well-being of both parents is a significant contributor on the behavioural and emotional development of preterm children,” said study lead author Dr Mira Huhtala, a researcher at Turku University Hospital in Finland.

Babies born prematurely have a greater risk of behavioural, emotional and neurological problems, probably for multiple reasons. Preemies endure a great deal of stress in the neonatal intensive care unit, noted Dr Deborah Campbell, director of neonatology at Montefiore Medical Centre in New York City. While it’s not clear exactly how that stress might affect a baby, Campbell said it may cause changes in the developing brain. She said that preemies also have smaller brain volumes on average, and overall they’re just not as developed as they should be.

At the same time, their parents are incredibly stressed and less resilient. The premature birth of their child may lead to lowered expectations, and they may be overly fearful, which may limit the child’s opportunities for normal development, she noted. If parents are depressed or feeling a sense of loss, they may not engage or connect with the child as well, said Campbell.

“It’s difficult to know how much of behaviour is from underlying biology and how much is the influence of the family,” she said.

In an attempt to tease out which factors might matter more, Huhtala and her colleagues evaluated 140 parents of very low birth-weight children born before 37 weeks of gestation (40 weeks is considered full-term). Very low birth weight means a baby weighs less than 1,500 grams (about 3.3 pounds) at birth.

Background data was collected on the parents at the time of birth. When the babies turned 2 years old, their parents were asked to complete psychological well-being questionnaires, and researchers assessed the children’s behaviour.

Just before the children’s third birthday, parents completed a questionnaire about the child’s behaviour. Parents were assessed for depression, stress and “sense of coherence.” Sense of coherence is “readiness to successfully coordinate and take advantage of personal resources,” according to the study.

“The more symptoms of poor psychological well-being (depressive symptoms, parenting stress, or weak sense of coherence) the mothers or fathers experienced, the more behavioural problems their children developed as reported by the parents,” Huhtala said. “The study showed that not only the psychological well-being of the mothers but also that of the fathers contributes to the behavioural problems of preterm children.”