Steroid injections given to pregnant women before premature birth may increase the child’s risk of later behavioral and emotional problems, according to a new study.

Mothers expected to give birth prematurely are routinely given an infusion of glucocorticoids, which mimic cortisol, a natural hormone. This is designed to help the baby’s lungs mature, but there is concern that exposure to high levels of glucocorticoids in the womb might have harmful long-term effects on brain development.

Researchers have previously established a link between stress in pregnancy and symptoms of attention-deficit/hyperactivity disorder (ADHD) in children. As cortisol is produced in response to stress, it has been suggested by some that cortisol may be responsible for this link, the researchers noted.

For this latest study, researchers at Imperial College London and the University of Oulu in Finland studied 37 children who were exposed to synthetic glucocorticoids before birth and compared them to 185 children who were born at the same gestational age, but did not have glucocorticoid treatment.

A larger comparison group of 6,079 children, matched on pregnancy and infant characteristics, was also examined to confirm the findings, the researchers noted.

The participants were part of the Northern Finland Birth Cohort, a study that recruited women in early pregnancy in 1985-1986 and gathered information about the health of the children at age 8 and 16.

The researchers found that children who had been exposed to synthetic glucocorticoids had poorer scores on general mental health at ages 8 and 16, and were more likely to show symptoms of ADHD.

“There are a lot of studies that have found links between stress in pregnancy and effects on children’s mental health, especially ADHD, and this might be related to cortisol,” said Alina Rodriguez, Ph.D., senior author of the study and a Visiting Professor at the School of Public Health at Imperial College London.

“Synthetic glucocorticoids mimic the biological reaction when the mother is stressed, so we wanted to see if babies who were exposed to this treatment are affected similarly in terms of mental health outcomes.”

The study suggests there may also be long-term risks for the child’s mental health, she noted.

“Although this is the largest study so far to look at these risks, the number of children in our group who were exposed to glucocorticoids was still relatively small,” Rodriguez said. “More studies will be needed to confirm the findings.”

The researcher was quick to reassure parents that “in light of all available evidence to date, the benefits of steroid treatment on immediate infant health and survival are well-established and outweigh any possible risk of long-term behavioral or emotional difficulties.”

“Parents who are concerned that their child may be affected by behavioral or emotional difficulties should in the first instance contact their GP for advice,” she said.

The study is published in the journal PLOS ONE.

This article first appeard on ‘Psych Central’ on 23 November 2013.