When a mother is expected to give birth prematurely, she is often given an infusion of glucocorticoids, a steroid treatment vital for helping the baby's lungs mature. Yet steroid injections given to pregnant women before premature birth may increase the child's risk of later behavioral and emotional difficulties, suggest researchers from Imperial College, London, and the University of Oulu, Finland. The study appears in PLOS ONE.

"This study suggests there may also be long-term risks for the child's mental health,” Alina Rodriguez, Visiting Professor at the School of Public Health at Imperial College London and senior author of the study, stated in a press release. “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. More studies will be needed to confirm the findings.”

Cortisol Link to Mental Health

In the late stages of pregnancy, cortisol is produced in the fetus to help the lungs develop. Among those premature babies who miss this vital stage of development, lung problems often develop, causing life-threatening breathing difficulties. Synthetic glucocorticoids have been found to replicate the effects of natural cortisol. Administered before birth, betamethasone, a type of glucocorticoid, reduces perinatal mortality and morbidity; dexamethasone, another glucocorticoid, is often administered after birth to temporarily improve respiratory function.

However, it has been known for some time that use of glucocorticoids too early in an infant’s life may interfere with brain development. Additionally, scientists have established a link between stress during pregnancy and symptoms of attention-deficit/hyperactivity disorder (ADHD) in children. As cortisol is produced as a response to stress, it has been suggested that cortisol may be responsible for this link and so some researchers have hypothesized that exposure to high levels of glucocorticoids in the womb might produce similar, harmful effects.

To investigate this theory, a team of researchers examined the records of 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 much larger comparison group of 6,079 children, matched carefully on pregnancy and infant characteristics, was also examined to confirm the findings. All of the participants were part of the Northern Finland Birth Cohort, a study that recruited women in early pregnancy in 1985-86 and gathered information about the health of the children at age eight and 16.

What did the researchers discover? The children who had received the glucocorticoid treatment had poorer scores on general mental health at ages eight and 16, and were more likely to show symptoms of ADHD.

“We would like 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/emotional difficulties,” Rodriguez stated in a press release.

ADHD is the most common behavioral disorder among young people in the U.K., affecting up to five percent of school-aged children. In the U.S., more than one in 10 (or about 11 percent) children are diagnosed with the disorder. Commonly, people with ADHD may have trouble paying attention, may act without thinking about consequences, and may be overly active. Although ADHD can't be cured, most children with the help of their parents are able to manage their condition and symptoms improve as they age.

Source: N. Khalife, Glover V, Taanila A, et al. Prenatal Glucocorticoid Treatment and Later Mental Health in Children and Adolescents. PLOS ONE. 2013.