SOURCES: Ryan Van Lieshout, M.D., Ph.D., assistant professor, psychiatry and behavioral neurosciences, McMaster University, Hamilton, Ontario, Canada; Brandon Korman, Psy.D., chief, neuropsychology, Miami Children's Hospital, Miami, Fla.; March 2015, online, Pediatrics
MONDAY, Feb. 9, 2015 (HealthDay News) -- People who were born very preterm may be at higher-than-normal risk of anxiety disorders and certain other mental health issues, even into their 30s, a new study suggests.
Those risks, researchers found, appeared particularly elevated among those who had been exposed to prenatal steroid medication.
Corticosteroids are commonly given to pregnant women in danger of preterm delivery, to help speed the baby's lung development and lower the risk of life-threatening complications.
It's not clear why the medications were tied to higher odds of mental health problems in adulthood, the study authors said. Only an association between the two was found, not a cause-and-effect link. The researchers stressed that expectant mothers should not be deterred from accepting prenatal steroids.
"I wouldn't want anyone to get that message," said Dr. Ryan Van Lieshout, an assistant professor of psychiatry and behavioral neurosciences at McMaster University in Hamilton, Ontario, Canada.
Instead, he said, parents and doctors should be aware of the increased mental health risks, and look out for signs of any problems as low birth weight kids grow older.
The findings, published online Feb. 9 in Pediatrics, give a picture of how tiny preemies fare as they move through adulthood.
It's well known that those infants have increased risks of later problems, including autism, attention problems and difficulty with social skills, said Brandon Korman, chief of neuropsychology at Miami Children's Hospital.
It's not clear, though, whether or how often any past studies weighed prenatal steroid use, said Korman, who was not involved in the new research. And he cautioned that it's early to draw conclusions.
"While this study suggests a connection between prenatal steroids and later psychiatric issues," he said, "that's confounded by comparison against [normal birth weight] 'controls,' rather than comparing premature individuals with and without prenatal steroid exposure."
For the study, Van Lieshout's team interviewed 84 adults who were born from 1977 to 1982 at an "extremely low" weight -- less than 2 pounds, on average. They were compared with 90 adults the same age, but born at a normal weight.
Overall, the study found, the preterm group was more than twice as likely to have an anxiety disorder, depression or attention-deficit/hyperactivity disorder (ADHD).
The risks were particularly elevated among adults who'd been exposed to prenatal steroids. Their odds of social phobia, for instance, were six times higher, versus the normal birth weight group, while their risk of ADHD was about 10 times higher.
Still, Van Lieshout stressed, those relative risks sound more troubling than they are.
Of 84 adults in the preterm group, only eight had ADHD, for example. Similar numbers had social phobia, general anxiety or major depression.
"The relative risks are quite high," Van Lieshout said. "But it's certainly not a sure thing that these problems will occur."
The fact is, he said, many adults who were born very preterm are living happy, healthy lives.
What's more, prenatal and newborn care has made big advances since the people in this study were born. So it's "entirely possible," Van Lieshout said, that the long-term outlook for preemies born in recent years will be different.
As for why adults in this study faced higher mental health risks, there could be a number of explanations, Van Lieshout said. For one, he said, tiny preemies are often subjected to medical procedures, and those "early-life stressors" may have lasting developmental effects in some cases.
Also, as a group, preemies have more health problems and a greater risk of low IQ than their peers -- which could affect their mental well-being, he said.
Preemies do, however, seem to have a lower risk of at least one mental health issue: alcohol and drug abuse. In this study, the preterm group was less likely to have problems with substance abuse, though that "protective effect" was not seen among those exposed to prenatal steroids.
What might explain the steroid findings? Van Lieshout agreed that there's uncertainty. The medications do cross the placenta, he said, and could potentially affect the fetal brain, but this study does not prove that's the case.
"The findings definitely need to be replicated in other studies," Van Lieshout said.
"We know that steroids are very important for moms to get before delivery, if they're in danger of preterm birth," he added. "I wouldn't want anyone to avoid steroids because of this."
The American Academy of Pediatrics has more on preterm babies' health issues.